Iraqi soldiers and police backed by helicopters and tanks on Monday battled militants for control of a northern town that has repeatedly changed hands in recent days, officials said.
Militants on Thursday took part of Sulaiman Bek and nearby areas in Salaheddin province, north of Baghdad, setting off a cycle of clashes with security forces.
Accounts of the death toll vary, but officials say that dozens of people have been killed, including security personnel, militants and civilians.
Local official Talib al-Bayati told AFP on Monday that security forces had succeeded in regaining control of Sulaiman Bek and surrounding areas.
But another official, Shallal Abdul Baban, said that only about 60 percent of the area was back in government hands.
Baban said security forces were advancing slowly, searching house by house, and that there were sporadic clashes as well as sniper fire from militants.
After initially seizing territory on Thursday, militants were pushed back the following day.
But security forces then withdrew for unknown reasons, Bayati said, and the militants regained control of part of the town on Saturday and later made further gains.
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The situation in Sulaiman Bek is a small-scale version of the crisis playing out in the mostly Sunni Anbar province west of Baghdad, where anti-government fighters have held the city of Fallujah and part of Ramadi for weeks.
The takeovers in Anbar mark the first time anti-government forces have exercised such open control in major cities since the bloody insurgency that followed the US-led invasion of 2003.
More than 370,000 people may have been displaced by the Anbar violence, according to the United Nations.
Sulaiman Bek has been hit by numerous attacks over the past year, and was briefly seized by militants in late April.
In July, some 150 militants struck with mortar rounds, rocket-propelled grenades and automatic weapons, and executed 14 Shiite truck drivers on a nearby highway.
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 to undercut support for militants.
But Prime Minister Nuri al-Maliki has taken a hard line ahead of a general election scheduled for April.