BAGHDAD -- In what appeared to be a new phase in an intensifying conflict that has raised fears of greater bloodshed and a wider sectarian war, Iraqi soldiers opened fire from helicopters on Sunni gunmen hiding in a northern village on Wednesday, officials said.
The air attacks were among clashes throughout the country between forces of the Shiite-dominated Iraqi government and Sunni gunmen that left at least 27 people dead and dozens wounded. The Sunni tribesmen were continuing a fight that began on Tuesday after the Iraqi Army stormed a Sunni protest encampment in the village of Hawija, leaving dozens dead and injured.
Several others were killed on Wednesday in explosions, including the detonation of a car bomb at a public market in the evening in a Shiite neighborhood north of Baghdad, and a roadside bomb attack on an army patrol in Tikrit, also in the north.
The deadliest battles occurred near Hawija and Sulaiman Pek, northern towns near Kirkuk, and battles were still raging in the early evening. In Hawija, the army shut off electricity, and troops shouted through loudspeakers, urging civilians to evacuate, witnesses said. Government helicopters also fired at Sunni gunmen on the ground in Sulaiman Pek.
The Sunni uprising, having now turned violent, represents a significant challenge to the rule of Prime Minister Nuri Kamal al-Maliki, whose consolidation of power over the security forces and the judiciary, and his targeting of high-level Sunni leaders for arrest, has raised alarms among world powers. Mr. Maliki has presided over an unwieldy power-sharing government, which nominally gives prominent roles to Sunnis but in reality has resulted in political stasis, and he has signaled in recent months that he would prefer to move to a majority government, dominated almost solely by Shiites. On Tuesday, two Sunni ministers quit to protest the raid in Hawija, and the largest bloc of Sunni lawmakers suspended participation in Parliament.
Mr. Maliki made no public comments on the situation Wednesday, but on Tuesday, after being pressed by American officials and the United Nations, he said he would open an investigation into the events in Hawija, and promised to hold military officers accountable for any mistakes.
The deteriorating situation in Iraq highlights the sectarian tensions that have risen across the region, particularly amid the raging civil war in Syria. There, a largely Sunni rebellion is seeking to topple the government of Bashar al-Assad, which is dominated by Alawites, who belong to a branch of Shiite Islam. In Iraq, the central government has aligned with the Syrian government and its greatest ally, Iran, while Sunnis here have sided with the rebels, and they now appear to be emboldened by the events in Syria to challenge their own government.
The sectarian fissure is evident in the rhetoric of the Sunni rebellion here: militants over the last few days have referred to Iraq's army as a force loyal to Iran, while many Shiites here have cast the formerly peaceful Sunni protesters as Muslim extremists beholden to Al Qaeda.
In other areas of the country, militants, their faces covered in checkered keffiyehs, attacked army positions. In Tuz Khormato, also near Kirkuk, militants ambushed an army convoy, killing four soldiers and setting fire to vehicles. In Baji, north of Tikrit, gunmen also attacked a convoy, resulting in a gunfight that left five militants and one soldier dead, according to a security official in Tikrit.
Amid the mayhem, Sunni leaders of formerly peaceful protests, which have been going on since December and grew from a deep sense of marginalization at the hands of the Shiite-controlled government, said they would now resort to violence to achieve their aims. This has raised fears that Friday, the Muslim Sabbath and traditionally the day when protests are at their most fevered, could result in even deadlier clashes.
In Hawija, which has long been a hideout for an insurgent group made up of former members of Saddam Hussein's Baath Party and called the Men of the Army of Naqshbandia Order, a spokesman for the protesters said the demonstrators would regroup as an "armed wing" of the Naqshbandia group.
"We started to collect money from tribal and civic leaders to buy weapons and face the army," said Abdul Malik al-Jabouri, the spokesman.
In Anbar Province, the epicenter of the Sunni grievances and the protest movement, leaders on Tuesday had given an ultimatum to security forces stationed in the area: leave within 48 hours, or armed tribesman would attack their bases. In the last day, protest camps in Anbar -- in Ramadi, the provincial capital, and in Falluja -- have become bases for armed militants.
"We lost faith in the government," said Ahmed Abdul Rahman, a sheikh and imam at a mosque in Ramadi, who in the past had been a voice of moderation. "Now most of the people in Anbar are carrying weapons. Anybody who says that it's still a peaceful demonstration is lying."
The clashes on Tuesday in Hawija killed nearly 50, mostly civilians, and injured more than 100, according to a final tally released Wednesday by Kirkuk's health department. Many of the wounded were transferred to cities in Iraq's semiautonomous Kurdish region in the north, where the quality of medical facilities is better.
The clashes there represented the deadliest violence to result from months of protests in Sunni cities across the country. Security forces had surrounded the camp for days after gunmen attacked a checkpoint and then, officials said, retreated to safety amid the protest gathering.
Duraid Adnan and Yasir Ghazi contributed reporting from Baghdad, and employees of The New York Times from Kirkuk, Nineveh, Salahuddin, Diyala and Anbar Provinces.
This article originally appeared in The New York Times.