MEXICO CITY (AP) — Mexican President Andrés Manuel López Obrador said Thursday many migrants believe the “doors are open” to the United States following the election of President Joe Biden.

López Obrador said that wasn’t true, and urged migrants not to believe traffickers who tell them they could get legal status immediately. He noted that he welcomed Biden's policy proposal, but that it would take time to be approved and implemented.

“Now, for example, that there is a U.S. immigration policy to regularize the situation of migrants, Mexicans and our Central American brothers, people think that now the doors are open, that President Biden is going to immediately regularize all migrants,” López Obrador said.

“It is not true that everyone can go now to the United States and they will be regularized, that has not been defined yet," he said. “Our brother migrants should have this information so that they won't be deceived by human traffickers, who paint a rosy picture.”

The Mexican leader also cited the recent massacre of 19 people, including at least 14 Guatemalan migrants, as justification for his policy of stopping Central American migrants at Mexico’s southern border.

López Obrador said the massacre showed that it was too dangerous to allow migrants to travel through drug cartel turf in northern Mexico.

“This was always our argument, that we need to protect migrants, watch out for them,” he said. “If they enter (Mexico) and spread out, we cannot keep an eye on them or protect them, and they wind up in the hands of organized crime, they are in danger.”

Twelve members of an elite police force in the northern border state of Tamaulipas have been charged in the Jan. 22 killing of the 14 Guatemalans and at least two suspected Mexican migrant traffickers. They were killed, their bodies piled in a pickup truck and burned so badly that three corpses have still not been identified.

Under pressure from former U.S. President Donald Trump in 2018 and 2019, López Obrador posted thousands of immigration, military and National Guard agents at Mexico's border with Guatemala to stop caravans of Central American migrants from entering the country.

Rights activists say Mexico's policy has exposed migrants to additional dangers, including excessive use of force by law enforcement forces, extortion by criminal gangs and violations of their human rights.