Armed tribes seized part of Sulaiman Bek town and nearby villages in northern Iraq on Thursday, local officials said, the latest instance of authorities losing ground to militants.
The latest flareup began with attacks by tribesmen armed with light and medium weapons on army positions before they overran the town centre early Thursday, local official Talib al-Bayati said.
Some called over mosque loudspeakers for residents to leave, Bayati said, adding that the army had now surrounded the area and helicopters were flying overhead.
Another local official, Shallal Abdul Baban, said armed tribes were in control of western Sulaiman Bek and three nearby villages.
He reported sporadic clashes in the area, and said that two police had been wounded.
Iraqi authorities face a far more serious problem in Anbar province, west of Baghdad, where tribal fighters opposed to the authorities have held all of the city of Fallujah and parts of provincial capital Ramadi for weeks.
Violence in Iraq has reached a level not seen since 2008, when the country was just emerging from a period of brutal sectarian killings.
Foreign leaders have urged the Shiite-led government to do more to reach out to the disaffected Sunni Arab minority but Prime Minister Nuri al-Maliki has taken a hard line ahead of a general election scheduled for April.