Five soldiers were killed Saturday in central Iraq by Sunnis demonstrating against Shiite Prime Minister Nuri al-Maliki, said Major General Mardi Mishhen, the head of military operations in Anbar province said, DPA reported.
The killings occured near a protest camp.
Mishhen gave the protest organizers in Falluja city "a 24-hour deadline to hand over the gunmen who killed the soldiers, or else the army will attack the camp" to search for the culprits.
Security forces imposed a curfew in the province until Sunday morning.
"I call on the peaceful demonstrators to expel criminals who target army and police forces," al-Maliki said in a statement, and vowed that the government would not keep silent over the killings.
Sheik Ahmed Abu Risha, the leader of the pro-government Sunni militia in Anbar province, offered a 50-million-dinar (43,100-dollar) reward for anyone who captured those responsible for killings.
"The demonstrators are innocent of such a crime committed by infiltrators. The Anbar tribes will hunt down the culprits, who will not go unpunished," he said.
Saturday's incident comes after around 53 people were killed and 110 injured Tuesday in clashes that followed the army's crackdown on Sunni protesters in the town of Heweja near the oil-producing northern city of Kirkuk.
The clampdown further infuriated Iraq's Sunni minority who have held mass protests for four months, demanding al-Maliki repeal laws they claimed target Sunnis.
The army said gunmen had infiltrated the anti-government protesters, who had camped out for weeks in a public square in Heweja. The protesters insisted that their sit-in was peaceful.
The crackdown prompted three Sunni ministers to quit al-Maliki's Shiite-led government and triggered violence in several areas of the country.
More than 100 people were killed in Iraq this week, raising fears of a return to the sectarian unrest that drove the country to the brink of civil war in 2006 and 2007.
In Baquba city, around 60 kilometres north-east of Baghdad, six policemen were killed in two separate attacks targeting security checkpoints.