At least 55 people have been killed and 95 injured after armed men stormed a government building in the northern Iraqi city of Tikrit immediately after a suicide bomber detonated explosives that cleared the way for the attack.
"A suicide bomber detonated his explosives belt outside the provincial council building in Tikrit, and immediately after that gunmen stormed into the building," a police official told the AFP news agency on Tuesday.
Another provincial official said the men, who wore security forces' uniforms, threw hand grenades and opened fire at a checkpoint of the Salahuddin provincial council building before they managed to storm it.
Al Jazeera's Rawya Rageh, reporting from the capital Baghdad, said officials told her none of the hostages were spared.
"They were shot at point-blank range, execution style ... and in a rather horrific account, the council spokesman said the bodies of three councilmen, who were among the hostages, were set on fire after they were killed."
Our correspondent said all the assailants involved in the attack were killed.
There has been no claim of responsibility, but the spokesman of the council, Mohammed Al Assi, told Al Jazeera that the attack "clearly bears the hallmarks of al-Qaeda in Iraq because of its nature, and the use of suicide vests".
Our correspondent said this was the first such attack since the siege on a Baghdad church in November.
"A police official told me that the assailants were highly trained, and the incident resembled that of a Hollywood action film," she said.
According to military officials, some US soldiers "received minor wounds," when responding to the attack.
"Iraqi forces took control of the scene and conducted further operations to secure the area. [We] are not aware of any US troops being directly involved in these operations. Our assistance has been limited to providing aerial surveillance of the scene and keeping our soldiers on site to receive further requests for assistance if needed," the army said in a statement.
The attack has also claimed the life of a freelance journalist working for the Reuters news agency.
Sabah al-Bazee suffered shrapnel wounds in an explosion, according to his cousin Mahmoud Salah.
Salahuddin province, home to Saddam Hussein's family, continues to suffer frequent attacks by fighters opposed to the the government in Baghdad.
In mid-January, a suicide bomber blew himself up and killed at least 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.
Iraq's security forces are now solely responsible for the country's security, with the US having declared a formal end to combat operations in the country at the end of August.
Al Jazeera and agencies