Security forces stormed the provincial council building in former dictator Saddam Hussein's hometown of Tikrit on Tuesday after an hours-long shootout with gunmen that left 58 dead and 97 wounded, a police official said.

"The latest toll is 58 dead and 97 wounded, and there are many with serious injuries, Six of the dead were the attackers," said the official, stationed at Tikrit's main hospital."

"The security forces have now taken over the provincial council building," a police official said, adding that three council members were among the dead.

The gunmen, wearing military uniforms and suicide vests, had swarmed into the provincial council building in the city of Tikrit, about 160 kilometres (100 miles) north of Baghdad, immediately after a suicide bomber detonated his payload and cleared the way, according to security officials.

A car bomb exploded shortly afterwards as police reinforcements were arriving, they said.

"A police colonel, Imad Nofan, and his deputy were killed in the car bombing," the police official said. The same explosion also killed journalist Sabah al-Bazi, who had reported for several local and international news organisations, the police official and other sources said.

Hospital sources said they had received the bodies of six attackers. They said two showed they had died after detonating their suicide vests, and four were killed by shots fired by security forces.

For several hours, it was unclear whether hostages were being held or how many. Police said employees were still inside the building while witnesses said that at least some had managed to flee from another exit.

It later emerged that some people were trapped inside, but details of how many, or what happened during the drama, remained sketchy.

"Police cannot approach because the gunmen are shooting from inside," a police official said during the stand-off. "The attackers are all wearing suicide belts."

He added that at least one had detonated his payload inside. He said all were dressed in military uniforms.

The attack began before 1 pm (1000 GMT) and lasted for more than four hours.

Shortly afterwards, a curfew was imposed in Tikrit, capital of the Sunni-majority Salaheddin province, which has long been a bastion of a Sunni insurgency and remains the scene of bloody attacks.

In mid-January, a suicide bomber blew himself up and killed 50 people in a crowd waiting outside a police recruitment centre in Tikrit.

That blast, which also wounded up to 150, was the first major strike in Iraq since the formation of a new government on December 21.

There was no immediate claim of Tuesday's attack, but officials said it bore the hallmark of Iraq's Al-Qaeda affiliate.

Iraq's security forces are now solely responsible for the country's security, with the United States having declared a formal end to combat operations in the country at the end of August.

At least four people were killed in other violence around Iraq on Tuesday.

Three brothers, including a military cadet, were shot early morning in their home in western Baghdad, according to a source at the Ministry of Defence.

Dr Mohamed Hussein, dean of the dentistry at Baghdad's Moustansiriya University, was killed Tuesday evening by a "sticky bomb" attached to his vehicle in Baghdad, an interior ministry official said.

Violence across Iraq has declined substantially since its peak in 2006 and 2007, but attacks remain common.