'Friday of Martyrs' appeal

Supporters of deposed president Morsi were preparing for a “martyrs” protest on Friday, prompting fears of renewed violence between demonstrators and police.

The pro-Morsi National Coalition to Support Legitimacy and Reject the Coup named 28 mosques in the Cairo area as departure points for demonstrations against the legitimacy of the interim government.

"We will remain steadfast on the road to defeating the military coup," said a statement from the coalition.

At least 900 people are believed to have been killed in the last eight days, according to government sources. Activists say the number is far higher.

Morsi, who was democratically elected last year, was deposed by the military on July 3, and is being held at an undisclosed location. He faces charges relating to his escape from prison in 2011 and inciting the deaths and torture of protesters.

Crackdown intensifies

Action against supporters of Morsi's Muslim Brotherhood continued on Thursday, with some 80 followers reported to have been taken into custody. Among those who had already been detained are the Brotherhood's supreme guide Mohamed Badie.

Meanwhile, former leader Hosni Mubarak, who led the country for almost three decades before he was toppled from power in 2011, was freed from jail into house arrest in a military prison where, according to the official MENA news agency, he chose to be held.

Mubarak was last year sentenced to life imprisonment for failing to stop the killing of demonstrators during the unrest that deposed him. However, a retrial was ordered earlier this year after a successful appeal by the 85-year-old former leader, who has now already served the maximum period of pre-trial detention.

The release of Mubarak, a long-standing opponent of the Brotherhood, appeared to prompt little in the way of an immediate reaction from Morsi supporters.

Balancing act for Washington

The United States, a staunch backer of the Egyptian military, has criticised the violence on the part of both the protesters and security forces. Washington has also announced the cancellation of joint military exercises.

Washington on Thursday avoided direct comment on Mubarak's release, but repeated an earlier call for Morsi to be freed.

"With respect to the Mubarak trial and decisions made, this is an internal Egyptian legal matter," said State Department spokeswoman Jen Psaki. "Our position on Mr. Morsi remains the same. We believe there should be a process for his release," Psaki said.

The US has stopped short of halting its $1.3 billion (970 million euros) annual defence aid package to Egypt.

rc / ch (AFP, AP, Reuters)