The Iraqi military has resorted to air power to dislodge al-Qa'ida militants in Sunni-dominated Anbar province, unleashing airstrikes and besieging the regional capital in fighting that killed at least 34 people, officials said.
Recent gains by the insurgents have been a blow to the Shiite-led government in Baghdad, which has seen sectarian violence rise since the withdrawal of US combat troops in 2011.
US Secretary of State John Kerry said Washington was "very, very concerned" by the fighting but would not send in American troops.
A ministry statement said the air force struck a militants' hideout overnight, identifying them as belonging to the al-Qa'ida-linked Islamic State in Iraq and the Levant, which the government refers to as "terrorists".
The army and allied tribesmen also fought al-Qa'ida militants around the provincial capital of Ramadi on Sunday, two Anbar government officials said.
They added that 22 soldiers and 12 civilians were killed, along with an unknown number of militants, and 58 people were wounded.
Clans inside the city of Fallujah have started to form brigades, they said, and some of the factions who fought the Americans following the US-led invasion a decade ago say they do not want the Iraqi army to enter the city.
According to the United Nations, Iraq had the highest annual death toll in 2013 since the worst of the country's sectarian bloodletting began to subside in 2007. The UN said violence killed 8,868 last year. (© Daily Telegraph, London)