Egyptian authorities are rounding up activists ahead of the fifth anniversary of the Jan. 25 uprising that toppled longtime autocrat Hosni Mubarak and have detained at least five people this week.

Among those detained were three activists, including prominent physician Taher Mokhtar, who were detained in police raids at their apartments in downtown Cairo on Thursday, according to lawyer Mukhtar Munair.

A forth person, poet Omar Hazek, was detained and quickly released but banned from leaving the country, according to a Facebook posting.

Also, managing editor of the privately owned Masr al-Arabia news website, Ahmed Abdel-Gawad, was detained after security forces raided its office on Thursday, according to a statement from the outlet. He was released on Friday, a second statement said.

The detentions are the latest in what has been a persistent and extensive crackdown on Islamists and secular activists alike, launched after the military's 2013 ouster of Mubarak's successor, Islamist President Mohammed Morsi.

The Egyptian government labeled Morsi's group, the Muslim Brotherhood, a terrorist organization. Thousands of Brotherhood members have been sentenced to death or life imprisonment while others are standing trials or detained without formal charges.

As in the past years, Egyptian authorities fear mass protests on the anniversary of the anti-Mubarak uprising and former army chief-turned-President Abdel-Fattah el-Sissi warned such protests could result in chaos.

In addition to the crackdown on activists, authorities have raided arts venues and galleries popular among youth activists.