A prominent Egyptian dissident has been arrested, six months after his release from prison, his family says.
Alaa Abdel Fattah was freed in March after serving a five-year sentence for organising a protest without permission.
He was a leading campaigner during the 2011 uprising against former Egyptian President Hosni Mubarak.
Under his probation conditions, the activist was required to spend nights in a police cell for five years.
On Sunday, as Mr Abdel Fattah was preparing to leave the police station, he was rearrested by Egyptian authorities, his family say.
"I arrived at the police station and I found the place where he spends the probation empty," his sister Mona told Reuters news agency.
Reports say Mr Abdel Fattah was arrested over allegations of publishing false news and inciting people to protest.
Human rights groups say about 2,000 people have been arrested since scattered anti-government protests erupted in Cairo and other cities last week.
The protests were in response to corruption allegations against Egyptian President Abdel Fattah al-Sisi's government.
Under President Sisi, there has been a wide-ranging crackdown on dissent and protests are very rare.
Public gatherings of more than 10 people without government approval have been banned since 2013, when Mr Sisi led the military's overthrow of Egypt's first democratically elected leader, Mohammed Morsi.
Who is Alaa Abdel Fattah?
Mr Abdel Fattah was a leading secular figure in the 2011 revolt that toppled Hosni Mubarak, who had ruled Egypt for almost 30 years.
The blogger and software engineer was once described by authorities as "the icon of the revolution".
After the ousting of Mubarak, Mr Abdel Fattah was arrested over his protests against trials of civilians before military tribunals, known for their swift and harsh rulings.
Mr Abdel Fattah also opposed Muslim Brotherhood leader Mr Morsi.