Updated

A government airstrike killed 25 Al Qaeda-linked militants in a besieged province west of Baghdad amid fierce clashes Tuesday between Iraqi special forces and insurgents battling for control of the key cities of Fallujah and Ramadi, Iraqi officials said.

The Al Qaeda gains in the Sunni-dominated province of Anbar -- once bloody battlegrounds for U.S. troops -- pose the most serious challenge to Prime Minister Nouri al-Maliki's Shiite-led government since the departure of American forces in late 2011.

Iraqi forces and fighters from government-allied Sunni tribes have been battling militants to try to recapture the strategic territory, seized last week by an Al Qaeda-linked group known as the Islamic State in Iraq and the Levant.

Iraqi military spokesman Gen. Mohammed al-Askari said the Iraqi air force struck an operations center for the militants on the outskirts of Ramadi, the provincial capital, killing 25 fighters who were holed up inside.

He didn't give more details about how the death toll was confirmed but cited intelligence reports. It was not possible to independently verify the military's claim.

The airstrike came after clashes erupted about 12 miles west of Fallujah following the capture of an army officer and four soldiers in the area a day earlier, provincial spokesman Dhari al-Rishawi told The Associated Press.

There was no immediate word on casualties for those clashes.

Al-Maliki's government has vowed to rout the militants, calling on Fallujah residents Monday to expel the Al Qaeda fighters to avoid an all-out battle.

Iraq's Cabinet met Tuesday to discuss the situation in Anbar and called for the mobilization of all efforts "to support the army and security services in expelling terrorists," according to a government statement.

Military operations would continue, the Cabinet statement added, until Iraq is "cleansed" of terrorism.

Residents of Fallujah have been streaming out of the city, 40 miles west of Baghdad, fearing an impending assault, according to witnesses.

A medical official in Fallujah said two civilians were killed and five were wounded, including two children, when they were caught Tuesday in an exchange of fire between militants and Iraqi army troops south of the city. The official spoke on condition of anonymity as he was not authorized to release information.

The immediate trigger for the unrest was the Dec. 28 arrest of a Sunni lawmaker sought on terrorism charges, followed by the government's dismantling of a months-old anti-government Sunni protest camp in Ramadi.

Sectarian tensions in Iraq have been rising for much longer as Sunni complaints grew that the government was targeting the minority community unfairly with what they alleged were random arrests on terrorism charges and discrimination. It was a U.S.-backed revolt by Sunni tribal leaders against Al Qaeda that led to a decline in the sectarian violence that followed the 2003 U.S.-led invasion that ousted Saddam Hussein, and the current unrest has raised fears the country was again being pushed to the brink of civil war.

Violence spiked after the government staged a deadly crackdown on a Sunni protest camp last April. Militants have also targeted civilians, particularly in Shiite areas of Baghdad, with waves of coordinated car bombings and other deadly attacks.

The attacks continued Tuesday when a suicide bomber rammed his explosives-laden truck into a police station in the northern city of Kirkuk, killing two people there and wounding 55, some critically, according to Maj. Raid Emad Rasheed.

A roadside bomb struck an army patrol southeast of Baghdad, in the Madain area, killing one soldier and wounding another, a police official said. Another bomb hit a patrol of pro-government Sunni militiamen in Baghdad's southeastern suburb of Jisr Diyala, killing one fighter and wounding four, he added.

A medical official confirmed the casualty figures. Both officials spoke on condition of anonymity as they are not authorized to talk to the media.

The death toll in 2013 was the highest in Iraq since the worst of the sectarian bloodletting began to subside in 2007, according to United Nations figures. The U.N. said violence killed 8,868 last year.