ISIL militants have killed a senior Kurdish commander and five other fighters after launching a major offensive in the Iraqi province of Kirkuk.
Fighting erupted around midnight as the insurgents launched mortars at Kurdish peshmerga positions in four districts southwest of the city.
An officer told Reuters news agency they had recaptured one district but that clashes were ongoing in the other three.
Heavily armed suicide bombers reportedly tried to take up positions in a hotel, but were killed by security forces.
More than 70 were reportedly wounded in the clashes.
ISIL militants, who now control large swathes of the north and west of Iraq have held areas on the outskirts of Kirkuk but have never taken the city.
Meanwhile, security sources said at least 18 people were killed in twin bombings in downtown Baghdad.
A suicide blast at a busy market went off, followed by a car bomb which killed many people who went to help those injured in the initial explosion.
Bombings by ISIL militants in Baghdad are frequent, on Thursday 21 people died in attacks at five different locations around the city.
In the holy city of Samarra, 125 kilometres north of the capital, police said two suicide bombers targeted a checkpoint killing three and wounding five members of the police and Shi’ite militias.
Officers say they thwarted a third attempted suicide attack by shooting a suspected militant. Clashes then erupted on the outskirts of the city following another explosion, with police and militia battling ISIL fighters.