Armed men wearing military uniform have broken into the city council headquarters in the Iraqi city of Samarra, holding the facility for four hours until police and army stormed the compound, officials say.
At least four policemen were killed in Tuesday's attack, along with three civilians who were visiting the city council and were shot when Iraqi security forces opened fire to retake the site, Reuters news agency quoted a senior police officer as saying.
A further 47 people were wounded, including 30 soldiers and policemen, according to officials at the Samarra hospital.
The deputy head of the city council, Ammar Ahmed, and a second member were wounded.
"The Iraqi police and army managed to clear the building," Samarra Mayor Mahmoud Khalaf said.
"The situation is under control."
Three fighters, who had holed up in the city council building, detonated their suicide vests rather than surrender, Khalaf said.
The three had stormed the area after a fourth detonated his vest at the entrance of the compound, which is sealed off with blast walls, Police Lieutenant Dhafir Ahmed said.
Two policemen had been racing to help when a parked car bomb blew up their vehicle about 200m from the site.
The attack in Samarra follows a similar incident in Tikrit, another city in the central Salaheddin province, where fighters detonated a car bomb and seized the city council headquarters on December 16.
Security forces ultimately freed the Tikrit hostages, but a city council member and two police were killed.
The attacks illustrate the impunity with which fighters in Iraq can strike even targets that should be highly secure.
Violence in Iraq has reached a level not seen since 2008, when the country was just emerging from a brutal period of sectarian violence in which tens of thousands died.
More than 1,750 people have been killed in attacks and clashes in Iraq since January 1, according to AFP figures based on security and medical sources.
Nouri al-Maliki, Iraq's prime minister, says the surge is a spillover from the civil war in neighbouring Syria but critics say his own policies are at least partly to blame for reviving an insurgency that climaxed in 2006-07.