Prominent activists Alaa Abdel-Fattah and Ahmed Maher have said they will hand themselves in to the prosecutor-general on Saturday.

They are accused of inciting Tuesday's unauthorised protest against military trials of civilians.

"For the second time the office of the Prosecutor general lets itself be a tool of government propaganda, this time on the orders of the murderer, (Minister of Interior) Mohamed Ibrahim, instead of the Supreme Guide (of the Muslim Brotherhood). Their reason: that I incited people to demand that trials should be fair and should be the responsibility of an independent civil judiciary," Abdel-Fattah said in a Facebook statement written in English.

"As though it’s bad for the prosecutor’s office to respect itself and be respected by the public, it must prove its subservience to any authority that passes through this country – no difference here between prosecutors illegitimately appointed under the instructions of the MB supreme guide, and Prosecutor correctly appointed – but at the instructions of the Military," he added, attacking Prosecutor-General Hisham Barakat.

"I have decided to do what I’ve always done and hand myself in to the Public Prosecutor. I do not deny the charge – even though I cannot claim the honour of bringing the people into the street to challenge the attempts to legitimize the return of the Mubarak state," he said, adding that he considers the current regime to be illegitimate.

April 6 Youth Movement said its founder and former coordinator Ahmed Maher would hand himself in to the prosecutor-general on Saturday.

"Despite attempts to clone the Mubarak regime, we want to show the public that we do not fear accountability as long as we are right. We do not fear speaking the truth," the group said in a statement.

On Wednesday, the prosecutor-general ordered the arrest of Abdel-Fattah and Maher for inciting and organising Tuesday's unauthorised protest against military trials of civilians in front of the Shura Council.

The protest was organised by the No to Military Trials of Civilians group. Security forces dispersed the protest because it had not been given prior authorisation as required by a new law. Dozens of people were arrested and some are still being detained.

Other activists have also handed themselves over to the prosecutor-general for organising the protest, including Mona Seif, who is Abdel-Fattah's sister and founder of the anti-military trials group.