Demonstrators gathered Saturday in front of the prosecutor general's office in downtown Cairo to demand the release of Revolutionary Socialist Haitham Mohamedein.

Mohamedein, a labour lawyer, was arrested at a military checkpoint close to Suez Thursday and ordered detained for an extra four days Friday. He is expected to stand before the prosecution Saturday. However, the charges against him are as yet unclear.

“Until this moment we cannot state exactly why he was arrested,” Tarek Shalabi from the Revolutionary Socialists told Ahram Online. “But for him to be arrested while riding a bus with others to meet workers who needed his help, then this is a political case.”

Shalabi went on to say that for him the arrest was not unexpected, and he believes more revolutionary figures will be targeted in the coming period.

“The military are not only targeting the Islamists. They will be after any revolutionary front, that includes the Revolutionary Socialists,” said Shalabi.

Since the ouster of Islamist president Mohamed Morsi, many Muslim Brotherhood leaders and allies have been arrested and charged with a variety of offences, mainly inciting violence.

“The capitalist state fears nothing more than labour strikes, and that's why they’d arrest someone like Haitham,” added Shalabi.

The protest, which was called for by the Revolutionary Socialists, was also joined by members of the April 6 Youth Movement, the Egyptian Current Party, in addition to several revolutionary figures, such as activist Alaa Abdel-Fatah and TV anchor Reem Magued.

Protesters held banners demanding the “release of all detainees.” One protester held a banner saying: “Watch out you’re in the state of Mubarak.”

Demonstrators also chanted for Mohamedein, saying: “Raise your voice up and chant; Haitham has never known fear!"

Anti-military slogans chanted at the protest, such as “Down with military rule” or “El-Sisi, you butcher,” provoked some passersbys who gathered in a small demo and chanted “The people and the army are one hand.”

Protesters later moved to the nearby Journalists Syndicate to protest the detention of Sinai-based award-winning journalist Ahmed Abou Deraa who was referred to military prosecution Thursday and given 15 days in detention, pending investigations on charges of broadcasting false information about the military, communicating with "terrorist groups" in Sinai, filming military property and provoking the armed forces.

Meanwhile, another protest in solidarity with Mohamadein was held in Egypt's second largest city of Alexandria in front of Al-Bahareyia Court on Mansheya square.

Lawyers representing Mohamedein are in Suez to attend his questioning by the prosecution, according to Ragia Omran, one of the attorneys representing him.