Cairo - The Muslim Brotherhood said early on Monday that police had moved in on a protest in Cairo in support of deposed President Mohammed Morsi.
There were many casualties, spokesperson Gehad el-Haddad said on his Twitter feed.
On Friday, three people were reported to have been killed at the same location as the sit-in protest at the Republican Guards Club, according to Al Jazeera television.
Political demonstrations continued in Cairo on Monday, the channel reported, as Egyptians waited to see who would be appointed as the country's interim prime minister.
Egyptian newspaper al-Ahram quoted sources as saying that Ziad Bahaa el-Din, a lawyer who was a founding member of the Egyptian Social Democratic Party, had been offered the premiership.
But there had been no "final nor official" decision on the post, the newspaper quoted El-Din as saying.
The reported appointment was rejected by the president of the influential Islamist Al Nour Party, which also objected to suggestions that Nobel Laureate Mohammed ElBaradei had been offered the post.