The Houthis moved into al-Manasseh area in al-Bayda province under cover from Katyusha rocket fire from the Yemeni army and presidential guard. Tribal sources said the Ansar al-Sharia fighters withdrew to another district called Bakla, some 3 km (two miles) away.

The Houthis have advanced into central and western Yemen since they seized control of Yemeni capital Sanaa on Sept. 21, taking on Sunni tribesmen and al Qaeda militants.

Fighting has flared up in several provinces, alarming neighbor Saudi Arabia, the world's No. 1 oil exporter.

The Yemeni army had so far avoided clashing with the Houthis or to support them in their advance on al Qaeda strongholds. But President Abd-Rabbu Mansour Hadi considers Al Qaeda in the Arabian Peninsula (AQAP) as the main threat facing the country.

One tribal leader said the Houthis exploited old rivalries between two wings of one of the main tribes in the area, the Al al-Dhahab tribe, and managed to enter the area, which had long been the main stronghold of Ansar al-Sharia, the local wing of Al Qaeda in the Arabian Peninsula (AQAP).

Houthi officials made no comment but group's television station said Houthi fighters and their allies have "reached the home of the leader of the criminal gangs" in al-Manasseh, referring to Ansar al-Sharia.

A U.S. drone on Friday struck al Qaeda targets in al-Manasseh killing at least three people, tribal sources said.

Local sources said on Sunday that Abdel-Ra'ouf al-Dahab, the local leader of Ansar al-Sharia, and a number of Saudi members of the group were killed in the strike. Officials could not confirm the report.

Tribal sources on Saturday said that al Qaeda militants and their tribal allies killed dozens of Houthi fighters in Radda and pushed back the rebels' advance on the town, where some 60,000 live.

They said al Qaeda fighters surrounded the Houthis on a mountain in Radda at dawn and killed dozens of them and took 12 prisoners forcing them to retreat to Dhamar province although clashes continued in other parts of the city.

The northern-based Shi'ite Houthis established themselves as power brokers in Yemen last month by capturing Sanaa against scant resistance from the administration of Hadi, who appears not to have a full grip on the country's fractious military.