Iraqi soldiers backed by tanks retook control of a Sunni town north of Baghdad on Friday after gunmen withdrew without a fight, although violence erupted at three Sunni mosques and clerics called for the formation of a tribal army to protect Sunni cities.

The Sunni gunmen had seized Suleiman Beg on Thursday after a firefight with security forces, one in a string of incidents that have left more than 170 people dead in Sunni Muslim towns in western and northern Iraq during the past four days.

Police and military officials said army units entered Suleiman Beg after negotiations with local tribal leaders.

The growing turmoil prompted the top U.N. official in Iraq, Martin Kobler, to warn Friday that the country is “at a crossroads.” The unrest in the country followed a deadly security crackdown on a Sunni protest in the northern town of Hawijah four days ago.

In Iraq’s predominantly Sunni provinces, antigovernment rallies continued as preachers at protest sites called for a tribal force to protect Sunni areas.

In Samarra, Sunni cleric Najih al-Mizan lashed out at what he said were “the policies of tyranny and repression” adopted by Iraqi Prime Minister Nouri al-Maliki. He said Maliki’s resignation was the only solution to save the country from the current crisis.

“We call upon our tribes to form an army that can protect us from a government that does not hesitate to kill its people,” said al-Mizan.

In Fallujah, Sunni cleric Ali al-Basra repeated the call to form a tribal army to protect Sunni cities. Several protesters held aloft al-Qaeda flags during the rally.

In western Baghdad, a bomb blast hit Sunni worshipers as they were leaving a mosque after Friday prayers, killing five. Minutes later, a Sunni was killed when a bomb struck Sunnis near a mosque in the Rashidiya area, 12 miles north of the capital. A bomb also exploded near a third Sunni mosque in northeastern Baghdad, killing two people.

There was no claim of responsibility for the mosque attacks.

Also Friday, police said a bomb exploded shortly after sunset near a small restaurant in Baghdad’s Shiite neighborhood of Sadr City, killing four people. Later, police said three people were killed when a car bomb went off in a commercial street in southern Baghdad.

Al-Qaeda’s Iraqi branch, known as the Islamic State of Iraq, frequently carries out attacks against civilian targets such as mosques, markets and restaurants. It mainly attacks Shiites but has also struck Sunni targets in an attempt to reignite the sectarian strife that almost resulted in civil war in the years after the 2003 U.S. led-invasion.

— Associated Press