Security forces clashed on Wednesday in Yemen's third largest city of Taiz with followers of the opposition, which is seeking the overthrow of President Ali Abdullah Saleh.
Seven people were wounded in the violence, witnesses said.
On-and-off clashes between government forces and armed tribesmen who appointed themselves to defend protesters have paralyzed Taiz, 200 km (120 miles) south of Sanaa, and other protest hubs. Yemen is entering its sixth month of mass protests calling for an end to Saleh's three-decade rule.
Security forces fired shots into the air to disperse 5,000 protesters who marched near Republican Guard barracks chanting anti-Saleh slogans and rallying against Saudi and American interference in Yemeni affairs.