In this image made from video, People’s Liberation Army soldiers, with brooms, arrive to clean up the protest area at Hong Kong Baptist University in Hong Kong, Saturday, Nov. 16, 2019. Troops from the Chinese army joined an effort to clean up debris outside the university, which was the site of clashes this week. (Television Broadcasts Limited Hong Kong via AP)

HONG KONG (AP) — Chinese troops came out of the barracks in Hong Kong on Saturday — not to quell protests but to help clean up.

It was a rare public appearance by the People’s Liberation Army on the streets of the semi-autonomous territory, where the local government’s inability to end more than five months of often violent protest has fueled speculation that Beijing could deploy its troops.

The Hong Kong government said that it had not requested the military’s assistance in the cleanup, describing it as a voluntary community activity.

Running in formation with brooms instead of rifles, they chanted in military cadence before joining street cleaners removing debris near Hong Kong Baptist University, where police fired tear gas at protesters earlier this week.

Most anti-government protesters left Hong Kong’s universities after occupying them for about a week. Police were facing off late Saturday night with a group that remained in and around Hong Kong Polytechnic University in an apparent attempt to flush them out.

For a city now accustomed to fierce weekend clashes between police and protesters, Hong Kong had a relatively quiet Saturday. Small contingents of protesters harassed some of those cleaning up, and those at Polytechnic kept a major cross-harbor tunnel closed. About 1,000 people turned out for an annual Gay Pride event in the center of the city.

Dozens of Chinese troops, dressed in black shorts and olive drab T-shirts, came out from a nearby barracks to pick up paving stones, rocks and other obstacles that had cluttered the street and prevented traffic from flowing. Hong Kong riot police kept watch from nearby streets.

China, which maintains a garrison of about 10,000 soldiers in Hong Kong, publicly noted several times earlier during the protests that it could deploy them, though technically it would have to be requested by Hong Kong’s government.

Doing so, however, would incur international criticism and revive memories of the army’s bloody crackdown on pro-democracy protesters at Tiananmen Square in 1989.

Police advanced toward the protesters at Polytechnic with tear gas around 10:30 p.m. After a hiatus, police and protesters traded volleys of tear gas and gasoline bombs as the clash extended past midnight.

Earlier, there were scattered incidents of protesters arguing with people clearing roadways, and in one instance, throwing a gasoline bomb near City University of Hong Kong.

Protesters also massed near Hong Kong University in the evening to try to block a main road again, but they were stopped by police firing pepper-spray balls.

Traffic disruptions continued to plague parts of Hong Kong, and schools and universities remained closed in the city of 7.5 million people. Now in their sixth month, the anti-government protests have grown increasingly violent even as they have shrunk in size, often causing chaos in the streets.

The protests were sparked by a government decision to submit legislation that would have allowed the extradition of criminal suspects to the mainland. Activists saw it as an erosion of Hong Kong’s autonomy under the “one country, two systems” formula implemented in 1997, when Britain returned the territory to China.

The bill has been withdrawn, but the protests have expanded into a wider resistance movement against what is perceived as the growing control of Hong Kong by Communist China, along with calls for more autonomy for the territory.

Universities have become the focus of the protests in the past week and the main battleground between pro-democracy activists and the police. The presidents of nine universities issued a joint statement late Friday calling on the government to resolve the political deadlock and restore safety and public order.

“No political viewpoint gives a license to damage property, employ physical threats, or use violence against individuals,” the statement read in part. “It is regrettable that societal disagreement has led to university campuses becoming major political battlefields, and that the government response has so far not been effective.”

Many universities have canceled classes for the rest of the year and hundreds of foreign students, and from mainland China, had left or were leaving Hong Kong. Some protesters targeted mainland students, while foreign students were asked to leave by their universities or governments.

Hong Kong media reported Saturday that at least 300 Dutch exchange students were asked by their home universities to return home because of the violence.

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Associated Press news assistant Nadia Lam contributed to this report.

In this image made from video, People’s Liberation Army soldiers, dressed in shorts and T-shirts pick up bricks scattered by protesters at Hong Kong Baptist University in Hong Kong, Saturday, Nov. 16, 2019. Troops from the Chinese army joined an effort to clean up debris outside the university, which was the site of clashes this week. (Television Broadcasts Limited Hong Kong via AP)
In this image made from video, People’s Liberation Army soldiers, with brooms, arrive to clean up the protest area at Hong Kong Baptist University in Hong Kong, Saturday, Nov. 16, 2019. Troops from the Chinese army joined an effort to clean up debris outside the university, which was the site of clashes this week. (Television Broadcasts Limited Hong Kong via AP)
A woman tries to hold back riot police from approaching the Hong Kong University in Hong Kong on Saturday, Nov. 16, 2019. Most anti-government protesters abandoned their occupation of Hong Kong's universities Saturday, while the small contingents that remained harassed some of those cleaning up and kept a major cross-harbor tunnel closed. (AP Photo/Ng Han Guan)
An anti-government protester holds two Molotov cocktail as she waits for the arrival of riot police outside the Hong Kong Polytechnic University in Hong Kong on Sunday, Nov. 17, 2019. Most anti-government protesters left Hong Kong's universities Saturday after occupying them for about a week. Small contingents that remained harassed some of those cleaning up and kept a major cross-harbor tunnel closed. (AP Photo/Ng Han Guan)
An anti-government protester patrols the roof of a bridge overlooking the Cross Harbor Tunnel next to the Hong Kong Polytechnic University in Hong Kong on Sunday, Nov. 17, 2019. Most anti-government protesters left Hong Kong's universities Saturday after occupying them for about a week. Small contingents that remained harassed some of those cleaning up and kept a major cross-harbor tunnel closed. (AP Photo/Ng Han Guan)
Anti-government protesters sleep on a rooftop as day breaks over the Cross Harbor Tunnel in Hong Kong on Sunday, Nov. 17, 2019. Most anti-government protesters left Hong Kong's universities Saturday after occupying them for about a week. Small contingents that remained harassed some of those cleaning up and kept a major cross-harbor tunnel closed. (AP Photo/Ng Han Guan)
Anti-government protesters look out over the Cross Harbor Tunnel as the sun rises in Hong Kong on Sunday, Nov. 17, 2019. Most anti-government protesters left Hong Kong's universities Saturday after occupying them for about a week. Small contingents that remained harassed some of those cleaning up and kept a major cross-harbor tunnel closed. (AP Photo/Ng Han Guan)
A participant wears a rainbow mask as he joins the gay pride rally in Hong Kong, Saturday, Nov. 16, 2019. Rebellious students and anti-government protesters abandoned their occupation of nearly all of Hong Kong's universities Saturday after a near weeklong siege by police, but at least one major campus remained under control of demonstrators. (AP Photo/Ng Han Guan)
Police in riot gear gather near Hong Kong Polytechnic University in Hong Kong on Saturday, Nov. 16, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday, not to quell protests but to help clean up. It was a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory, where the local government's inability to end more than five months of often violent protest has fueled speculation that Beijing could deploy its troops. (AP Photo/Achmad Ibrahim)
An anti-government protester patrols the roof of an overhead bridge overlooking the Cross Harbor Tunnel next to Hong Kong Polytechnic University in Hong Kong on Sunday, Nov. 17, 2019. Most anti-government protesters left Hong Kong's universities Saturday after occupying them for about a week. Small contingents that remained harassed some of those cleaning up and kept a major cross-harbor tunnel closed. (AP Photo/Ng Han Guan)
An anti-government protester sleeps on a barricaded bridge overlooking the Cross Harbor Tunnel next to Hong Kong Polytechnic University in Hong Kong on Sunday, Nov. 17, 2019. Most anti-government protesters left Hong Kong's universities Saturday after occupying them for about a week. Small contingents that remained harassed some of those cleaning up and kept a major cross-harbor tunnel closed. (AP Photo/Ng Han Guan)
Protesters set fire to a barricade outside the Hong Kong Polytechnic University during the early hours of Sunday, Nov. 17, 2019. Most anti-government protesters abandoned their occupation of Hong Kong's universities Saturday, while the small contingents that remained harassed some of those cleaning up and kept a major cross-harbour tunnel closed. (AP Photo/Ng Han Guan)
Police in riot gear clear a barricade set by protesters near Hong Kong Polytechnic University in Hong Kong on Saturday, Nov. 16, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday, not to quell protests but to help clean up. It was a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory, where the local government's inability to end more than five months of often violent protest has fueled7speculation that Beijing could deploy its troops. (AP Photo/Achmad Ibrahim)
Journalists gather near fire left burning after protester retreat into the Hong Kong Polytechnic University in Hong Kong on Sunday, Nov. 17, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday to help clean up in a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory. (AP Photo/Ng Han Guan)
Protester look for police presence at the Hong Kong Polytechnic University in Hong Kong on Sunday, Nov. 17, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday to help clean up, in a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory. (AP Photo/Ng Han Guan)
Journalists stand near fire left burning as protesters retreated into the Hong Kong Polytechnic University in Hong Kong on Sunday, Nov. 17, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday to help clean up, in a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory.  (AP Photo/Ng Han Guan)
Protester scout the area outside the Hong Kong Polytechnic University in Hong Kong on Sunday, Nov. 17, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday to help clean up, in a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory. (AP Photo/Ng Han Guan)
Protester shines his torch to look out for police presence at the Hong Kong Polytechnic University in Hong Kong on Sunday, Nov. 17, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday to help clean up, in a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory. (AP Photo/Ng Han Guan)
Protestors rush to extinguish canisters of tear gas fired by police near the Hong Kong Polytechnic University in Hong Kong on Saturday, Nov. 16, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday — not to quell protests but to help clean up. It was a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory, where the local government's inability to end more than five months of often violent protest has fueled speculation that Beijing could deploy its troops. (AP Photo/Ng Han Guan)
Police in riot gear fire tear gas at protestors on a pedestrian bridge near the Hong Kong Polytechnic University in Hong Kong on Saturday, Nov. 16, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday — not to quell protests but to help clean up. It was a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory, where the local government's inability to end more than five months of often violent protest has fueled speculation that Beijing could deploy its troops. (AP Photo/Ng Han Guan)
Police in riot gear gather near the Hong Kong Polytechnic University in Hong Kong on Saturday, Nov. 16, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday — not to quell protests but to help clean up. It was a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory, where the local government's inability to end more than five months of often violent protest has fueled speculation that Beijing could deploy its troops. (AP Photo/Achmad Ibrahim)
Police in riot gear gather prepare to fire tear gas near the Hong Kong Polytechnic University in Hong Kong on Saturday, Nov. 16, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday — not to quell protests but to help clean up. It was a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory, where the local government's inability to end more than five months of often violent protest has fueled speculation that Beijing could deploy its troops. (AP Photo/Achmad Ibrahim)
Police in riot gear fire tear gas at protestors near the Hong Kong Polytechnic University in Hong Kong on Saturday, Nov. 16, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday — not to quell protests but to help clean up. It was a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory, where the local government's inability to end more than five months of often violent protest has fueled speculation that Beijing could deploy its troops. (AP Photo/Achmad Ibrahim)
Police in riot gear fire tear gas at protestors near the Hong Kong Polytechnic University in Hong Kong on Saturday, Nov. 16, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday — not to quell protests but to help clean up. It was a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory, where the local government's inability to end more than five months of often violent protest has fueled speculation that Beijing could deploy its troops. (AP Photo/Achmad Ibrahim)
People hold up their hands as they walk past riot police near the Hong Kong Polytechnic University in Hong Kong on Saturday, Nov. 16, 2019. Chinese troops came out of the barracks in Hong Kong on Saturday — not to quell protests but to help clean up. It was a rare public appearance by the People's Liberation Army on the streets of the semiautonomous territory, where the local government's inability to end more than five months of often violent protest has fueled speculation that Beijing could deploy its troops. (AP Photo/Achmad Ibrahim)
Police in riot gear fire tear gas at protestors near the Hong Kong Polytechnic University in Hong Kong on Saturday, Nov. 16, 2019. (AP Photo/Achmad Ibrahim)
Police in riot gear try to separate students and local residents near the University of Hong Kong in Hong Kong, Saturday, Nov. 16, 2019. Rebellious students and anti-government protesters abandoned their occupation of nearly all of Hong Kong's universities Saturday after a near weeklong siege by police, but at least one major campus remained under control of demonstrators. (AP Photo/Ng Han Guan)
Participants in a gay pride rally stand near graffiti reading
Demonstrators hold up their hands to represent the five demands of pro-democracy protestors during a gay pride rally in Hong Kong, Saturday, Nov. 16, 2019. Rebellious students and anti-government protesters abandoned their occupation of nearly all of Hong Kong's universities Saturday after a near weeklong siege by police, but at least one major campus remained under control of demonstrators. (AP Photo/Ng Han Guan)