At least 20 al-Qaida militants were killed early Thursday when the Yemeni army forces attacked various positions of the terrorist group in the turbulent southern province of Abyan, a senior army officer said.

Various militant positions and fortifications on the northeastern outskirts of Zinjibar city, the provincial capital of Abyan, were targeted in the large-scale army offensive, leaving at least 20 terrorists killed, the local army officer engaged in the fighting told Xinhua on condition of anonymity.

Five foreign militants were among the killed, including three Africans, the officer said, adding that "the army forces escalated the military operations against the al-Qaida group in an attempt to put an end to the fighting and drive the militants out of the seized cities soon."

Sources close to the al-Qaida terrorist group confirmed to Xinhua the toll, saying that "their hideouts were pounded by unprecedented heavy artillery bombings."

The al-Qaida militants threatened to launch retaliatory attacks against the army troops, according to the sources.

The al-Qaida in the Arabian Peninsula controlled several regions in the south part of the country, where clashes between government forces and the militants became regular after months of domestic protests calling for Yemeni President Ali Abdullah Saleh' s resignation.