Three suspected al-Qaida militants were killed when their vehicle was hit by a US drone strike in Yemen's southeastern province of Shabwa on Monday, a tribal chief told Xinhua.

Two missiles fired from a US drone destroyed the car and left the three dead bodies scattered in the area, said the tribal source.

Witnesses said that the air strike took place in Musinah area near Shabwa's provincial capital of Ataq city after repeated hovering of US drones over the area.

Armed confrontations erupted Sunday between members of the Yemen-based al-Qaida offshoot, Ansar al-Sharia, and pro-government tribesmen in Shabwa.

The clash left an unknown number of people killed from both sides, when southern tribesmen tried to prevent the al-Qaida militants from organizing meetings in the province, said local sources.

Ansar al-Sharia emerged in January 2009 and has become the most active regional al-Qaida insurgencies in the Middle East. It had claimed responsibility for a number of attacks on Yemen's army and government institutions.

It took advantage of the Yemen's security vacuum and the ongoing civil war to expand its influence in the southern regions.

The fragile security situation in Yemen has deteriorated since March 2015, when a war broke out between the Shiite Houthi group, supported by former President Ali Abdullash Saleh, and the government backed by a Saudi-led coalition.

More than 6,000 people have been killed in ground battles and airstrikes since then, half of them civilians.