ADEN: A suspected US drone strike killed two al Qaeda militants on Thursday in eastern Yemen, as an army offensive against the extremist group entered its sixth day, a local official said.

Speaking on condition of anonymity, the official said the two al Qaeda suspects were killed in a strike on their car in Shibam, a historic city in Yemen's Hadramawt province.

Air strikes on al Qaeda targets in Yemen have increased since the Yemeni army, backed by US experts, launched an offensive on Saturday to retake southern cities that in the last year had fallen under al Qaeda control.

At least 144 people have been killed in the last six days of fighting which has centred around the three cities of Loder, Jaar and Zinjibar in the southern Abyan province.

A military official involved in the offensive said on Thursday that al Qaeda gunmen retreated from three locations on the outskirts of Loder.

“We have cleansed Loder (of al Qaeda) and the fighters have been forced to flee,” said the official on condition of anonymity.

Al Qaeda remains in control of Zinjibar, Abyan's capital, though diplomats and officials said on Wednesday that the Yemeni military was advancing towards the southeastern entrance of the city.

One local official said on Thursday that the Yemeni airforce launched several late night airstrikes on the southern cities of Shaqra and Arqoub, both near Zinjibar, though no casualties were reported.

A force of around 20,000 soldiers from all regions in the south are believed to be engaged in the operation launched on Saturday.

They are backed by armed militias, mostly local residents of the towns and cities in the south that since the ouster of veteran leader Ali Abdullah Saleh and the election of a new president earlier this year have thrown their support behind the Yemeni military.