FILE - In this Feb. 10, 2011 file photo, Egyptian Wael Ghonim, center,  walks into Tahrir Square after Egyptian President Hosni Mubarak's televised statement to his nation, in downtown Cairo, Egypt.   Ghonim said late Thursday, Sept. 19, 2019 in a video on his twitter account that authorities raided his parents' house in Cairo and arrested his brother Hazem, whom he described as

CAIRO (AP) — The U.S.-based Egyptian activist whose Facebook page helped ignite the 2011 pro-democracy uprising said authorities have arrested his brother in Cairo.

Wael Ghonim, a computer engineer, said his recent criticism of Egyptian President Abdel-Fattah el-Sissi prompted authorities to retaliate by detaining his brother.

Ghonim alleged that the Egyptian Embassy in Washington warned him the day before the arrest.

"They told me if I did not stop speaking, something will happen," Ghonim said in a video posted on Twitter late Thursday.

He said authorities arrested his brother Hazem during a raid on his parents' home. Authorities confiscated his parents' passports and phones, Ghonim said.

Meanwhile, dozens of people on Friday held a rare protest in Cairo during which they called on el-Sissi to quit. Security forces dispersed the protesters and no casualties were reported.

The protest occurred near Tahir Square, the epicenter of the 2011 uprising that toppled longtime autocrat Hosni Mubarak.

Egypt outlawed all unauthorized protests in 2013. That's when el-Sissi, as defense minister, led the military's overthrow of an Islamist president amid mass protests against his brief rule.

The government crackdown that followed has rolled back the freedoms won in 2011. Tens of thousands of Egyptians have been arrested since 2013, and many have fled the country.

Wael Ghonim was among those who left. He had used social media to mobilize widespread protests against Mubarak.

FILE - In this Feb. 8, 2011 file photo, Egyptian Wael Ghonim, center, talks to the crowd in Tahrir Square, in Cairo, Egypt. Ghonim said late Thursday, Sept. 19, 2019 in a video on his twitter account that authorities raided his parents' house in Cairo and arrested his brother Hazem, whom he described as
FILE - In this April 26, 2011 file photo, Egyptian Internet Activist Wael Ghonim attends the Time 100 Gala, celebrating the 100 most influential people in the world in New York.   Ghonim said late Thursday, Sept. 19, 2019 in a video on his twitter account that authorities raided his parents' house in Cairo and arrested his brother Hazem, whom he described as