Ten people were killed when gunmen wearing explosive belts stormed a police building in the Iraqi city of Ramadi on Sunday, police and provincial officials said.
The attack in mainly Sunni Anbar province followed several weeks of bombings targeting Shi'ites after the eruption of a political crisis that has threatened to break up the coalition government and raised fears of renewed sectarian violence.
The assault in Ramadi, a onetime al Qaeda hotspot where militants frequently attack government facilities, provided a new test for Iraqi security forces without the support of U.S. troops, the last of which pulled out in mid-December, nearly nine years after the invasion that toppled Saddam Hussein.
Six gunmen, three policemen and a civilian died in the assault on the Ramadi police building, which houses an anti-terrorism unit and a jail, and 18 other people were wounded, police and hospital sources said.
One of the attackers detonated his explosive belt at the entrance to the police building and others tried unsuccessfully to take hostages but were turned away by intense gunfire from security forces inside, police and provincial officials said.
Three of the gunmen were killed by police gunfire and three blew themselves up, the last after he was cornered by security forces on a rooftop, the officials said.
Ramadi, the Anbar provincial capital, witnessed some of the worst violence during the height of the war that followed the 2003 U.S.-led invasion. It was the heart of a Sunni Islamist insurgency tied to al Qaeda.
Anbar tribal leaders and thousands of Sunni insurgents eventually turned against al Qaeda and formed the Sahwa militia, which joined U.S. forces and helped turn the tide of the war.
Iraqi security officials have expressed concern that al Qaeda may regroup in Anbar following the U.S. withdrawal.
Anbar has had testy relations with the central government recently, particularly following an arrest campaign against former members of Saddam's banned Baath party. Local officials have suggested Anbar might join other Sunni-majority provinces in seeking more autonomy.
Violence in Iraq has ebbed since the height of sectarian slaughter in 2006-2007 but Sunni insurgents and rival Shi'ite militias still carry out attacks almost daily. Insurgents often target local government buildings and security forces.
The attack in Ramadi came a day after a suicide bomber killed more than 50 people and wounded more than 100 in an attack on Shi'ite pilgrims passing through a police checkpoint in the southern city of Basra.
Tensions are running high in Iraq, four weeks after the last U.S. troops pulled out, following moves by the Shi'ite-led government against two Sunni political leaders and a series of bombings that have killed scores of Shi'ites.
(Reporting by Fadhel al-Badrani; writing by Jim Loney and Patrick Markey; Editing by Andrew Roche)