ADEN (AFP) - At least 25 soldiers have been killed in a friendly fire incident and clashes with militants linked to Al-Qaeda in south Yemen, security officials said on Sunday. The officials said some of the soldiers were killed in a strike by the Yemeni air force that mistakenly hit a school in the southern town of Zinjibar. Hundreds of militants from the Al-Qaeda-linked Partisans of Sharia group overran Zinjibar in May, and it has been the scene of bitter fighting. One military official told AFP on condition of anonymity that the air strike on the school killed a large number of soldiers. Al-Qaeda militants then attacked the school after the air strike and killed even more soldiers, he said, adding that at least 25 have so far been killed at the school. Officials at the military hospital in the nearby port city of Aden said they were unable to confirm the deaths as their ambulances have been unable to reach the location because of intense fighting between soldiers and militants. Zinjibar, the capital of the Yemens troubled southern Abyan province, and at least three other towns in the area were overrun by militants in May. Since then, troops have been battling to take back control of the region. Saturdays fighting came a day after one of Al-Qaedas top leaders in the Arabian Peninsula country, US-born cleric Anwar al-Awlaqi, was killed in an apparent US drone strike. Al-Qaeda in the Arabian Peninsula (AQAP) has taken advantage of nearly nine months of sweeping unrest against President Ali Abdullah Saleh to bolster its presence in the restive south and east Yemen, launching regular attacks.