Egyptian forces were questioning some 250 supporters of the former president on Saturday as the government promised to deal firmly with "powers of terrorism and sabotage."
Those detained - many arrested during clashes in central Cairo's Ramses Square on Friday - are under suspicion of murder, attempted murder and terrorism, state media said. More than 700 people have died in four days of violence, most of them supporters of the Muslim Brotherhood.
Blaming the Muslim Brotherhood for the bloodshed, Egyptian Prime Minister Hazem el-Beblawi said his government was now studying the possibility of dissolving the group.
"There will be no reconciliation with those whose hands have been stained with blood and who turned weapons against the state and its institutions," Beblawi said.
His comments came after violence as police cleared central Cairo's al-Fatah mosque, where Brotherhood supporters had sought refuge. State media report that Brotherhood followers exchanged gunfire with police who had earlier surrounded the building.
Nine marches planned
Police finally cleared the mosque on Saturday, and made a series of arrests. The Muslim Brotherhood meanwhile has called at least nine marches across the Egyptian capital for Sunday, with a plan to gather near the country's Constitutional Court.
Protesters are demanding the release of Morsi, who remains in custody at an undisclosed location.
Founded in 1928, the Muslim Brotherhood has a firm grounding in provincial Egypt, and won all five of the elections that followed the toppling of former President Hosni Mubarak in 2011.
However, the group was accused of incompetence and trying to monopolize the government. Hundreds of thousands of Egyptians took to the streets in June to demand that Morsi step down. The military forced Morsi from office on July 3.
rc / ch (AFP, AP, dpa, Reuters)