Violent clashes as Saleh refuses to bow out

At least three people were killed and 25 wounded in the fighting in Sanaa, the fiercest yet between the pro- and anti-Saleh camps, which raised fears that the collapse of efforts to negotiate a peaceful resolution to Yemen's three-month-old crisis could throw the country into a violent confrontation.

Hundreds of thousands of Yemenis have been holding protests since February demanding Mr Saleh's removal, and they have been hit by a bloody crackdown – but prior to yesterday there had been only minor armed clashes between the two sides.

The violence erupted outside the Sanaa home of Sheik Sadeq al-Ahmar, leader of Yemen's largest and most powerful tribe, the Hashid. Mr Saleh belongs to the tribe, but Sheik Ahmar announced in March that the Hashid were joining the popular uprising against the president.

Fighting raged for more than six hours yesterday, until the US ambassador mediated a cease-fire, according to a ruling party official. Abdel-Qawi al-Qabasi, an aide to Sheikh Ahmar, accused security forces of trying to storm the Hashid leader's compound and said tribal fighters counter-attacked. Some witnesses said security forces had been setting up roadblocks between the walled compound and the nearby Interior Ministry, which tribesmen saw as a provocation.

The Hassaba district was turned into a battle zone as tribesmen and security forces clashed outside the Interior Ministry, trading fire with automatic weapons and rocket-propelled grenades. An office building of Yemeni Airlines was on fire, and smoke poured out of a building inside theministry compound. Tanks were seen pulling into the neighborhood and the sound of tank fire was heard.