Iraqi forces fought for a second day Friday to seize control of a strategically located university in militant-held Tikrit ahead of a full-scale assault on the city, officers said.
A police major said there were periodic clashes between security forces and Sunni Arab insurgents at Tikrit University, and that the families of school employees living in the area were fleeing.
A senior army officer said Iraqi forces were carrying out a major campaign of air strikes on militants in Tikrit to protect the forces at the university and prepare for the assault.
Troops are deployed in areas around the city in readiness, the officer said.
The battle for the university began on Thursday when troops swooped in by helicopter to the hometown of executed dictator Saddam Hussein, seized by the militants on June 11.
The university is located on the way to the town of Baiji as well as to a military base to the north of the city that have both been overrun by militants, the officer said.
A major offensive, led by jihadists from the Islamic State of Iraq and the Levant but involving other groups as well, has overrun large areas of five provinces since it was launched on June 9.
Iraqi security forces folded during the initial onslaught but are now regrouping and performing somewhat better.