Sources tell Al Jazeera that at least 20 al-Qaeda suspects have been killed in US air attacks and clashes with Yemeni soldiers in the southern province of Abyan.

A military official confirmed on Thursday the deaths of the al-Qaeda-linked fighters, but refused to comment on whether there was any US involvement.

The air raids freed a Yemeni military unit besieged in Abyan for several weeks by al-Qaeda groups.

A medical official said four Yemeni military officers were also killed in clashes on Wednesday and Thursday.

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The official said Yemeni troops had pushed back al-Qaeda groups  from an area about 8km outside the southern city of Zinjibar.

The officials spoke on condition of anonymity because they were not allowed to speak to the press.

Yemen has repeatedly said its forces are making gains against groups who are suspected of ties to al Qaeda and have taken over two large cities in Abyan, a flashpoint province.

But the army has yet to regain control since the region was plunged into almost daily violence some months ago, bloodshed that has driven away some 90,000 residents.

President Ali Abdullah Saleh's government has lost control of some parts of the south amid rising political turmoil, as mass protests demanding an end to his 33-year rule.

The US and neighbouring oil giant Saudi Arabia fear that spreading chaos in Yemen is giving the branch of al-Qaeda entrenched there more room to operate.

Saleh's opponents accuse his government of exaggerating the al-Qaeda threat in Yemen and even encouraging armed groups in order to pressure Riyadh and Washington to back his continued rule.

Saleh is still recovering in Saudi Arabia from severe wounds during a June bomb attack but has vowed to return to Yemen, a course of action Washington has advised him not to pursue.

Source: Agencies