A police officer from Salaheddin province, where Samarra city is located, says five attackers were killed.
Daesh gunmen wearing suicide vests stormed a police station in the Iraqi city of Samarra on Monday, sparking clashes with security forces, officials said.
At least seven policemen were killed and an indefinite curfew was imposed on the city, according to security sources.
"There was a terror attack on Mutawakil police station, now the Iraqi forces are besieging them," Interior Ministry Spokesman Saad Maan told reporters. He said the attackers holed up inside the police station were exchanging fire with security forces.
The Daesh terrorist group claimed responsibility for the attack in central Samarra, a city 110 kilometres (70 miles) north of Baghdad, via its propaganda agency Amaq.
A police major from Salaheddin province, where Samarra is located, said five attackers had already been killed and added that reinforcements had been deployed.
Ammar Karim joins TRT World from Baghdad.
Samarra is home to a Shia shrine where a 2006 bombing touched off two years of sectarian violence.
Daesh claimed a similar attack in Samarra on November 28 last year, in which five gunmen wearing suicide vests killed at least four members of the security forces after infiltrating the city.