Twenty-three people have been injured in clashes between rival factions of Egypt's opposition Wafd party in the capital Cairo, police have said.
The trouble broke out early on Saturday
The violence erupted after deposed Wafd leader Nomaan Gomaa occupied the party headquarters and supporters of the new leaders tried to gain entry.
Eight people were reported to have been shot and 15 others injured, and the building was set on fire.
Mr Gomaa, 71, and six of his supporters were detained by police.
Doctors said three of the people shot were in a serious condition, Reuters news agency reported.
It added that police said those shot included journalists and party workers who were in the building when Mr Gomaa arrived at about 0800 local time (0600 GMT).
The fire in the building was brought under control.
Mr Gomaa, who came a distant third in last year's presidential elections, was deposed in January by a group he says are rebels.
He argues he is still Wafd leader, but since he was removed, the party has elected Mustafa al-Tawil as its president.
Mr Gomaa's former deputy, Mahmoud Abaza, was made party chairman.
The Wafd party has only six of the 444 seats in parliament.