A US drone strike killed at least four members of the Yemen-based al-Qaida branch in the southern province of Shabwa early on Tuesday, a security official told Xinhua.

The strike took place in Azzan town, some 60 km northeast of Ataq, the provincial capital, and killed at least four terrorists, the local security official said on condition anonymity.

"The target of the drone was the terrorists on a small pick-up truck, and some targets near al-Qaida-held sites were also destroyed," the official said.

Local military intelligence sources told Xinhua that the militants killed in the strike could be from Saudi Arabia and Yemen, but their exact nationalities are yet to be ascertained.

"The identities of the militants could not be verified because their bodies were badly mutilated," the source said.

The al-Qaida terrorist group has no comment on the strike yet.

The US government stepped up drone strikes in Yemen since Yemeni President Abd-Rabbu Mansour Hadi took office in February 2012, after a year-long unrest weakened the control of the central government and allowed the militants to take over swaths of territory in the south.

The Yemeni government managed to recapture several southern cities in May 2012.

However, on Jan. 23, a US drone strike targeting armed militants mistakenly hit a civilian house in the southeastern province of al-Bayda, killing two children, according to Yemeni officials.