Egypt’s authorities have moved swiftly to implement a new law restricting protests, arresting more than 50 people and seeking the detention of leading activists.

Among those seized is Alaa Abd El Fattah, a prominent blogger and activist who was held in late 2011.

Fellow activists say the security forces raided Abd El Fattah’s home late Thursday night, producing no search warrant and beating both him and his wife as their 2-year-old son slept in the next room.

Last weekend, the military-backed interim Government declared that unauthorized protests are illegal and those involved may be arrested. On Tuesday, at least 51 people were detained, and warrants were issued for Abd El Fattah — for the incitement and organisation of the protest — and for the arrest of Ahmed Maher, founder of the 6th April Youth Movement.

Abd El Fattah had said that he would turn himself in on Saturday, formally informing the Public Prosecutor’s office.

The activist was imprisoned by the Mubarak regime and by the interim government of the Supreme Council of the Armed Forces in 2011 as he returned from giving a keynote speech at a technology conference in San Francisco. He remained in prison for almost two months.

Abd El Fattah just before his imprisonment in November 2011: