Suspect held in Yemen over raid that killed 11

A military pick-up vehicle is set on fire after an ambush in Dalea city June 20, 2010.

SANAA (Reuters) - Yemeni security forces Sunday arrested the head of the group suspected of carrying out an attack on a police building in the southern city of Aden which killed 11 people, the Defense Ministry said.

Yemen blamed al Qaeda for Saturday's attack in which gunmen wearing military uniforms raided a police headquarters in the port of Aden, killing seven security officers, three women and a 7-year-old boy, and freeing several detainees.

"Security bodies in Aden succeeded in arresting the leader of the terrorist group which carried out the attack on the political security (police) building, killing a number of people and officers, women and children," a ministry website said.

It identified him as Ghodel Naji, who it said belong to terrorist groups and had "a long history of terror and crime" and was also wanted for an armed bank robbery last year.

Yemen is struggling to curb a separatist movement in the south and to cement a ceasefire with Shi'ite rebels in the north. It is under international pressure to quell domestic conflicts to focus on a growing al Qaeda presence in the country.

A day before Saturday's attack, al Qaeda's Yemen-based regional branch threatened to respond to a state crackdown against it in eastern Yemen, calling on local tribesmen to take up arms against the government.

Yemen, a neighbor of oil exporter Saudi Arabia, has been a growing security concern for the West since a Yemeni-based arm of al Qaeda claimed responsibility for an unsuccessful attempt to set off a bomb on board a U.S.-bound airliner in December.

POLICE OFFICERS KILLED IN AMBUSH

In a separate incident, suspected southern separatists ambushed and killed two Yemeni police officers on a routine patrol Sunday, despite a deal for calm in the flashpoint city of Dalea, provincial officials and state media said.

Separatists had agreed a deal two days earlier to end a weeks-long government siege of the city, with the government promising to remove roadblocks and the separatists agreeing to pull gunmen out of strategic points, the officials said.

Yemen's Western allies and Saudi Arabia fear a resurgent al Qaeda wing could exploit unrest and use Yemen as a base for attacks in the region and beyond.

The separatist movement in the south has gathered steam in recent months, with deaths on both sides, while a separate civil war with Shi'ite rebels subsides in a northern corner of the Arabian Peninsula state.

Tension has grown in Dalea, with government forces surrounding the city shelling separatist positions in town earlier this month and engaging in gun battles with secessionists.

After Sunday's ambush, in which suspected separatists set fire to a military vehicle after shooting dead the two police officers inside, security forces combed the city for the perpetrators. There was no immediate word on any arrests.

North and South Yemen formally united in 1990 but many in the south, where most of impoverished Yemen's oil facilities are located, complain northerners have used unification to seize their resources and discriminate against them.

(Reporting by Mohammed Ghobari, additional reporting by Mohammed Mukhashaf in Aden; Writing by Cynthia Johnston and Firouz Sedarat; editing by Andrew Dobbie)