Al-Qaeda has claimed an attack on a Yemeni army headquarters in a tightly secured district of Aden in which 20 people died, most of them militants, a monitoring group said Thursday.

Al-Qaeda has claimed an attack on a Yemeni army headquarters in a tightly secured district of Aden in which 20 people died, most of them militants, a monitoring group said Thursday.

The building targeted in Wednesday's attack is located in the heavily patrolled coastal district of Tawahi that hosts intelligence and political police headquarters, a naval base and a presidential residence.

Al-Qaeda in the Arabian Peninsula (AQAP) claimed the attack in an online message, said the US-based SITE Intelligence Group, which monitors extremist organizations.

AQAP said the attack killed "nearly 50 soldiers" and was part of its campaign "to "target the joint operation rooms that manage the US drones in the country".

Militants launched Wednesday's attack on the northern side of the army headquarters, with some climbing a wall into the building as a suicide car bomber rammed his vehicle into a western entrance, Yemen army officials said.

Reinforcements from the 31st Armored Brigade stationed in Aden were dispatched to support the troops in Tawahi, according to one official, who added that the fighting went on for several hours.

Six soldiers were killed and 14 wounded, while three civilians including a seven-year-old child also died, the official added. Ten of the assailants plus the suicide bomber died.

Despite repeated attempts by the army to crush AQAP in its strongholds in the east and south, militants continue to carry out deadly attacks on security forces across the country.