Firing automatic weapons and mortars, gunmen attacked the security building in Aden on June 19, killing at least 11 people. The attack was the bloodiest in Yemen since the bombing of the USS Cole in 2000 that killed 17 US sailors.

"This attack comes as a response to the tyrannical aggression that reached our people in Maarib province and deliberately humiliates the tribes with the pretext of fighting terrorism," a statement from Al-Qaeda's Yemen-based regional wing said in a statement posted on an Islamist website.

"Then they falsely claim that they struck the fighters with painful blows, but we didn't see anything except the killing of women and destruction of mosques and the striking of homes."

Yemen, next to top oil exporter Saudi Arabia, leapt to the forefront of Western security concerns after the Yemen-based Al-Qaeda wing claimed responsibility for a failed attempt to bomb a US-bound airliner in December.

The June attack in Aden came a day after Al-Qaeda threatened to respond to a state crackdown against it in the remote Maarib province, home to a militant stronghold in Wadi Obeida, calling on local tribesmen to take up arms against the government.

Al Qaeda put the death toll in the attack at 24, higher than that given by the government, and accused those killed of involvement in what it described as oppression designed to please Washington.

Yemen's Western and Saudi allies want Sanaa, also trying to cement a northern truce and quell southern separatism, to resolve domestic conflicts and consolidate power so that it can focus on fighting Al-Qaeda.

Yemen escalated a crackdown on Al-Qaeda this year, and further stepped up security measures after accusing Al-Qaeda of being behind the June attack.

Yemeni authorities arrested eight suspected Al-Qaeda militants over the past week, including a Saudi fugitive, accused of plotting attacks on security installations, the defense ministry said.

The arrests came days after two suspected members of the same Al-Qaeda cell were detained following a house raid in the eastern Hadramout province that sparked clashes in which three soldiers were killed.

A security official said the group arrested in Hadramout was accused of plotting attacks on security and other vital installations there, but did not identify specific targets.

The defense ministry identified the Saudi who was arrested as Abdullah Faraj Mohamed Mahmoud Al-Jawbar, who is on a list of 85 Saudis wanted by Riyadh. It added that authorities had found a suicide bomb belt during the house raid a week ago.