An air strike has killed 13 suspected al-Qaeda fighters in the central Yemeni province of al-Bayda, security and tribal sources said.

Tribal sources said a drone had been circling the region for days. They said the drone struck two cars early on Saturday that the suspected fighters were in, and added that three civilians in a nearby car were also killed, the Reuters news agency reported.

Yemen's defence ministry website quoted a security source as saying a number of "terrorists" had been killed in the air strike.

"An air strike targeted cars that suspected al Qaeda militants were in and killed 13 of them in the Sawma'a are of al-Bayda," a security source told Reuters.

Yemen is among a handful of countries where the US acknowledges using drones, although it does not comment on the practice.

Washington has stepped up drone strikes as part of a campaign against al-Qaeda in the Arabian Peninsula, which is based in Yemen and regarded by the US as one of the most lethal wings of the group.

Earlier this week, suspected al-Qaeda fighters shot dead the deputy governor of al-Bayda as he was leaving his home, according to a security official.

Al-Bayda has seen serious security incidents in the past. In December, 15 people on their way to a wedding were killed by an air strike after their party was apparently mistaken for an al-Qaeda convoy, according to security officials.

The Yemeni government said in a statement at the time that senior al-Qaeda fighters were targeted in the air strike. It did not say who carried out the attack.