The bomber blew up his vehicle at the entrance of Najda Camp in Abyan province's capital Zinjibar, 55 kilometers from second city Aden where the government is based.

The attacker failed to get through the gate and heavy exchanges of fire ensued as other assailants tried to penetrate it.

The explosives were concealed in the back of a pick-up truck under a pile of firewood, the sources said.

Al-Qaeda, which has taken advantage of nearly two years of fighting between loyalists and Houthis, claimed responsibility for the attack, the SITE Intelligence Group reported.

Further north, in the central province of Bayda, fierce clashes erupted Friday between pro-government tribes and Houthi Houthis, a local official said.

Twenty Houthis and six tribal fighters were killed in heavy fighting near Walad Rabi district, the source said, adding that the clashes flared when the Houthis tried to take control of a tribal territory.

Nine other Houthis died when tribal fighters ambushed their convoy in the Sawmaa region, another area of tension between Houthis and local tribes, the official said.

-File photo