Smoke poured out of the Interior Ministry building in Sana'a Tuesday during clashes that left some 66 people dead and hundreds of others injured.

A ministry official was quoted by the Chinese news agency Xinhua as saying the rebels led by Hashid tribe leader Sadeq al-Ahmar fired mortar shels and RPGs (rocket-propelled grenades) at the ministry and a nearby security camp, setting both ablaze. At least 15 security troops and one civilian were killed in the attack.

Government forces returned fire against Al-Ahmar's residential compound, killing 49 rebels as stockpiled ordnance was ignited.

Some 3,000 Houthi-led Shi'ite mercenaries were hired by Al-Ahmar to join the fight to oust Yemeni President Ali Abdullah Saleh, according to Houthi sources. The armed tribesmen were deployed in the northern province of Sa'ada.

Clashes erupted following Saleh's decision to back down from an agreement to sign a Gulf Cooperation Council-brokered deal to transfer power to opposition forces within 30 days.

“Yemen, I hope, will not be a failed state or another Somalia. The people are still keen for a peaceful transition of power,” Saleh told Reuters.

The besieged president blamed the Ahmar clan for trying to “drag us into civil war” and said the family “bears responsibility for shedding the blood of innocent civilians.” He added that he is willing to transfer power, but not to those who will threaten the security of the nation.