Islamic State jihadists Thursday seized a major road in northern Iraq after a surprise attack on government troops, a security official said.
Militants took control of the road linking the Kurd-controlled city of Kirkuk and the city of Tikrit that was regained by Iraqi forces from Islamic State in April, the official said on condition of anonymity.
"Clashes are continuing between Iraqi forces and Daesh elements," the official said, using an Arabic acronym for Islamic State. "Iraqi warplanes are bombing the group's positions in the area."
At least 12 militants and seven Iraqi soldiers were killed, he said.
Mosques in the district of al-Alam, about 20 kilometres from the site of the fighting, have called on civilians to carry weapons in anticipation of the militants' advance, residents said.
Last month, the Iraqi government announced the "liberation" of the western city of Ramadi from Islamic State, marking the first major setback for the al-Qaeda breakaway group since April.
Since Ramadi's recapture, Islamic State has carried out a series of attacks in several parts of Iraq where it still controls swathes of territory.