Islamic State in Iraq and the Levant (ISIL) fighters struck at Kurdish forces southwest of the Iraqi city of Kirkuk on Friday, while bombs in and near Baghdad killed 27 people, security and medical sources said.
Police in the northern province of Kirkuk said ISIL launched mortars and attacked positions of Kurdish peshmerga fighters in four districts southwest of Kirkuk City.
Since surging across the Syrian border last summer, ISIL has frequently battled security forces and Shia armed groups in the south and west of Iraq, but attacks on the outskirts of Kurdish-controlled Kirkuk have been rare.
A peshmerga officer told Reuters that his forces had recaptured the district of Mariam Bek, but said clashes were ongoing in Tal al-Ward, Maktab Khalid and Mullah Abdullah.
Medical sources said nine Kurdish fighters were killed in the fighting, including senior commander Brigadier Sherko Fatih. At least 70 others were wounded.
More than 750 peshmerga have been killed in combat since ISIL overran their defenses in northern Iraq last summer, prompting U.S.-led air strikes.
The Kurds have now regained most of the ground they lost in August. However, peshmerga commanders complain that they remain ill equipped compared to ISIL fighters, who plundered Iraqi arms depots when they overran Mosul in June.
Iraq has been facing its worst crisis since the 2011 withdrawal of U.S. troops, with ISIL now in control of about a third of the country.
Also on Friday, security sources said 19 people were killed and 28 wounded when two bombs went off in Baghdad's Bab al-Sharqi district.
Four civilians were later killed and 7 others were wounded in a separate incident in northwestern Baghdad, when mortars landed in residential neighborhoods, police and medics said.
Police officials also said that a suicide bomber drove his-explosive-laden car into a security checkpoint manned by Shia guards near the city of Samarra, 60 miles north of the Iraqi capital, killing four fighters and wounding 10 others.
It is not yet clear if ISIL carried out the Baghdad or Samarra attacks.
Al Jazeera and wire services