A curfew is in place in the Iraqi city of Kirkuk following fierce overnight clashes between Kurdish Peshmerga forces and Islamic State militants.
IS fighters used heavy weaponry and suicide bomb attacks against Kurdish Peshmerga forces to the south of the city in the early hours of Friday.
Six Peshmerga fighters were killed, including senior commander Brigadier Sherko Fatih.
At least 21 people were killed in other attacks in Baghdad and Samarra.
A number of Peshmerga fighters were also reported killed in another suicide attack at Jalawla, in Diyala province, despite recent assurances from Iraqi authorities that the area had been cleared of IS fighters.
The attacks indicate that, despite the setback IS has faced at Kobane in north-east Syria, the militant group is determined to keep up aggressive activity elsewhere, our correspondent Jim Muir reports from Beirut in Lebanon.
The so-called IS militants captured a number of villages to the south of Kirkuk during their overnight attack, though Kurdish officials say some of the ground was later regained in a counter-offensive.
In Kirkuk city itself, suicide bombers targeted a police station and nearby hotel.
The curfew kicked in at 10:00 local time (07:00 GMT) and will remain in place until further notice, reports say.
Kirkuk is home to several different groups, including Arabs, Kurds and Turkmen. All three groups have competing claims to the province, which is rich in oil.
Under former Iraqi leader Saddam Hussein's programme of "Arabisation", Kurds were driven from Kirkuk and replaced with settlers from the south, and the Iraqi government continues to assert control over nearby oilfields, with the backing from the local Turkmen community.
The city itself was seized by Kurdish fighters in June 2014 after the Iraqi army left the area ahead of an anticipated attack by Islamic State militants. It has come under regular attack from IS militants since then.