A security official said on Wednesday the clashes broke out late on Tuesday when militants attacked troops stationed near Zinjibar, the capital of the volatile Abyan province, where militants, emboldened by months of upheaval, have seized at least three towns since March.

Warplanes targeting the attackers bombed the area and residents of the town of Jaar, some 15 km away, said the sky was lit up by the raid.

Meanwhile, one army unit managed to force gunmen from a stronghold in the Maysameer district west of Zinjibar, a security official told Reuters.

“The militants withdrew, leaving behind weapons and materials they had previously looted from the army,” he said.

While Saleh recovers in Riyadh, Saudi Arabia, from a June assassination attempt, the death toll in Abyan has been rising fast, with militants regularly attacking soldiers, security officials and tribesmen who are fighting to regain control over parts of Yemen’s south.

A resident of Jaar said he had helped militants bury the bodies of the dead in a mass grave in the small hours of Wednesday morning and saw them crying and reciting the Qur’an.

On Monday, government warplanes killed six presumed Al-Qaeda fighters in Arkub, another village in Abyan province, that they had seized a day earlier.

Tribesmen siding with government forces are battling militants in Abyan, mainly in Zinjibar, where militants have besieged the army’s 25th Mechanized Brigade base since May.

The officials spoke on condition of anonymity because they are not authorized to talk to the media.

Militants have used Yemen’s political turmoil to overrun Zinjibar and several towns in the south.

Government forces have been trying to dislodge them with airstrikes and ground troops.

Analysts fear upheaval in impoverished Yemen is giving the militants more room to launch attacks on the region and beyond.

Opponents of Saleh accuse him of exaggerating the threat of Al-Qaeda and even of encouraging militants in order to pressure Riyadh and Washington into backing him.