* Back in Tahrir Square, protesters want Mubarak prosecution
* Protester frustrations include pace of corruption moves
* Protesters hold mock trial for Mubarak
* Military says nobody will have immunity
(Adds military comment from new armed forces newspaper)
By Shaimaa Fayed and Dina Zayed
CAIRO, April 8 (Reuters) - Protesters packed Cairo's Tahrir Square on Friday, piling pressure on the ruling military council to meet demands including the prosecution of Hosni Mubarak in one of the biggest demonstrations since he was ousted.
Thousands of people waved red, white and black Egyptian flags in scenes reminiscent of the height of the uprising that helped ignite protests against autocrats across the Arab world.
Hundreds of thousands crammed into Tahrir Square, the main theatre for the protests that swept Mubarak from power, leaving in charge the army led by Field Marshal Mohamed Hussein Tantawi.
"Tantawi, Tantawi get your act together or do you want a pool of blood?" chanted some of the protesters, expressing frustration over the pace of change that Egyptians hope will produce a democratic system of government.
The military has enjoyed broad support since it took control of the country on Feb. 11, but complaints against its rule are growing. Attention is now focused on the perceived tardiness of legal measures against Mubarak and his entourage.
Mubarak and his family have been living in the Red Sea resort of Sharm el-Sheikh since he left Cairo. The military has said the 82-year-old president, himself a former military officer, is banned from leaving the country.
"We will not give immunity to anyone. We will not cover up corruption and all are equal in front of the law," the military said in a new armed forces newspaper circulated on Friday.
The public prosecutor, who has filed charges against some but not all of the Mubarak-era officials, was also the focus of protester anger. They declared him "the sleeping prosecutor".
Lawyers and judges held a mock trial for Mubarak and some of his closest associates on charges of "corrupting Egypt politically and economically, committing crimes of torture and stripping us of our rights".
Military helicopters hovered over the city centre as protesters poured into the square after Friday prayers. Their demands included the removal of remaining Mubarak-era officials, such as the powerful provincial governors.
"It's a strong message that the revolution is not over yet and is still going on and will not quieten down before its goals are realised," said Hassan Nafaa, a professor of political science and a prominent figure in the reform movement.
The protest drew an array of Egyptians, from leftists to Islamists including the Muslim Brotherhood, a group considered Egypt's best-organised political force.
The military council has scheduled a parliamentary election for September and said a presidential election will be held in either October or November.
"Satisfying all in this transition period is impossible and democracy will not be achieved overnight or in six months," the military said in the new newspaper, part of a public relations campaign including a Facebook page.
Tahrir Square banners carried economic demands, including the imposition of minimum and maximum wages. "The revolution is continuing until democracy is achieved," read one banner.
"There has to be continued pressure for the quick and effective realisation of the demands of the revolution," a coalition of youth activists said in a statement. Street action was "the real guarantee" of success, it said.
At one point, eight young men in military uniform appeared on a stage in the square, calling for Tantawi's removal. The state news agency said investigations were underway to establish their identity and whether they were from the military.
The interim government installed by the military council has set up a committee to uncover corruption from Mubarak's 30-year rule. The illicit gains panel has said it will question Gamal Mubarak, the president's son, next week.
"There is a feeling that the military council faces many restrictions," Nafaa, the political science professor, said.
The campaign against Mubarak-era figures has resulted in the arrest of once untouchable figures including the former interior minister and other ministers who held economic portfolios and are accused of corruption.
Additional reporting by Isabel Coles; Writing by Tom Perry; Editing by Michael Roddy