More than 100 people have been killed in two days of violence across Iraq after a raid on a camp of mostly Sunni Muslim protesters on Tuesday ignited the fiercest clashes since US troops left.
On Wednesday, fighting broke out for a second day between government troops and protesters in the country's north, after the deaths of at least 56 people at a protest camp in Kirkuk province on Tuesday.
Troops stormed the camp where Sunni Muslims have protested for months against what they see as their marginalisation under the Shia-led government, a raid that prompted Sunni tribal leaders to call for revolt.
Many of the victims were killed in ensuing clashes, which spread beyond the town of Hawija near Kirkuk, 170km north of Baghdad, to other areas, reviving worries of a return to widespread intercommunal violence.
Al Jazeera's Omar Al Saleh, reporting from Baghdad, said clashes between fighters and the army were ongoing on Wednesday evening.
"The army is using helicopters. We also heard that gunmen are in charge of at least one police station and that hundreds of people have fled the area."
Fighters also took over an army base and burned a small Shia mosque in Sulaiman Pek, 160km north of Baghdad, before the army helicopters drove the fighters out of the town.
At least 18 were killed, including 10 fighters and five soldiers, officials said. An ambush on an army convoy near Tikrit with roadside bombs and rocket-propelled grenades killed three more soldiers.
In a separate development, at least eight people were killed and 23 more wounded when a car bomb exploded in eastern Baghdad, police and medical sources said on Wednesday. No one immediately claimed responsibility for the blast.
A surge in unrest has accompanied growing turmoil among the Shia, Sunni and Kurdish parties that make up Prime Minister Nouri al-Maliki's power-sharing government.
A decade after the US-led invasion, sectarian wounds are still raw in Iraq, where just a few a years ago violence between Shia armed groups and Sunni fighters killed tens of thousands of people.
Iraq last descended into widespread sectarian bloodshed in 2006-2007 after al-Qaeda bombed the Shia Askari shrine in Samarra, triggering a cycle of retaliation.
Thousands of Sunnis have been protesting since December, venting frustrations building up since the overthrow of Saddam Hussein and the empowerment of Iraq's Shia majority through the ballot box.
"We are staying restrained so far, but if government forces keep targeting us, no one can know what will happen in the future, and things could spin out of control," said Abdul Aziz al-Faris, a tribal leader in Hawija.
The two main Shia groups, Asaib al-Haq and Kataeb Hizbullah, appear to have stayed out of the latest violence. But former fighters said they could take up arms again if needed.
The Iraqi government said it was setting up a commission to investigate the string of attacks that erupted on Tuesday.
Al-Maliki has offered some concessions to Sunni protesters, including proposed reforms to tough anti-terrorism laws, but most Sunni leaders say they will not be enough to appease the demonstrators.