Iraqi Prime Minister Nuri al-Maliki warned Thursday of a return to "sectarian civil war" after 176 people were killed in three days and gunmen were given 48 hours to vacate a town they seized.
Maliki called for people "to take the initiative, and not be silent about those who want to take the country back to sectarian civil war," in remarks broadcast on state television.
The violence erupted on Tuesday when security forces moved in against anti-government protesters near the Sunni Muslim town of Hawijah in northern Iraq, sparking clashes that left 53 people dead.
A wave of subsequent unrest, much of it apparently revenge attacks for the Hawijah clashes, killed dozens more people and brought the toll by Thursday to 176 dead and 282 wounded.
The protest-related violence is the deadliest so far linked to demonstrations that broke out in Sunni areas of the Shiite-majority country more than four months ago.
The protesters have called for the resignation of Maliki, a Shiite, and railed against authorities for allegedly targeting their community, including with what they say are wrongful detentions and anti-terrorism charges.
On Thursday, attacks in Fallujah, west of Baghdad, killed two Sahwa anti-Al-Qaeda militiamen, two federal policemen, and wounded two more, police and a doctor said.
And a roadside bomb in Jurf al-Sakhr, south of Baghdad, killed two patrolling soldiers, according to police and a medic.
Security forces also killed four gunmen in Qara Tebbeh town in Diyala province, while three were killed and two wounded, then arrested, in Kafak near the northern city of Mosul, Staff General Ali Ghaidan Majeed told AFP.
The toll from heavy fighting on Wednesday in Mosul also rose, with officers and a doctor saying a further 31 gunmen and four police were killed, bringing the total to 40.
Meanwhile, Majeed told AFP that gunmen holding the town of Sulaiman Bek in Salaheddin province have 48 hours to disperse or face attack.
The gunmen swarmed into the predominantly Turkmen Sunni town on Wednesday after deadly clashes with the security forces, who pulled back in the face of the offensive as residents fled.
Local official Shalal Abdul Baban said gunmen were still in complete control of the town but that the army was deploying reinforcements on the outskirts.
The military said the operation in Hawijah that sparked the clashes was aimed at the Naqshbandiya Army, a band of Sunni militants it said had infiltrated the ranks of the anti-government protesters.
Two leaders of the Hawijah protest said on Thursday they would form a wing of the Naqshbandiya Army in response to Tuesday's killings.
"We in the Uprising of the Free People of Iraq announced our full loyalty to the (Naqshbandiya Army), so we can be an armed wing related to it, working on cleaning Iraq from Safavid militias," protest spokesman Hamed al-Juburi said.
Safavid is a pejorative word for Shiites.
"We will take revenge for the massacre of Hawijah," he said.
Protest organiser Abdulmalik al-Juburi said: "After they burned our tents and broke into our sit-in, we decided to join the (Naqshbandiya Army) as a military wing."