ADEN: In a surprise attack, al Qaeda militants stormed a prison in southeastern Yemen on Thursday, freeing several hundred inmates including one of their leaders, a security official said.

Two prison guards and five inmates were killed in clashes, the official said.

Qaeda militants stormed the center of the city of al-Mukalla, the capital of the southeastern province of Hadramawt, which was still controlled by pro-Hadi forces.

The militants also clashed with troops guarding the local adminstration complex in the city, a branch of the central bank and the police headquarters.

Khalid Batarfi, a senior Al Qaeda figure who had been held for more than four years, was among more than 300 prisoners who escaped from the jail in Hadramawt province, the official told AFP.

Batarfi is among Al Qaeda in the Arabian Peninsula's (AQAP) top regional commanders, known for his leading role in a 2011-2012 battle with Yemeni government troops during which extremists seized swathes of territory in the south and east.

The remote area is also the ancestral home of former al Qaeda leader Osama bin Laden, whose father was born in a valley before moving to neighbouring Saudi Arabia.

Yemen has descended further into chaos since a Saudi-led coalition launched air strikes a week ago against positions held by Shia rebels and their allies across the deeply tribal country.

Observers have warned that Yemen-based AQAP, classified by the United States as the network's deadliest franchise, could exploit the unrest to strengthen its presence in the country.