The attack occurred around noon when army helicopters dropped dozens of soldiers inside the university compound, a strategically located military base to the northern Tikrit, Xinhua quoted the source as saying on condition of anonymity.
Tikrit, 140 km northwest of Baghdad, was seized by armed militants of the Al Qaeda-inspired Islamic State of Iraq and Greater Syria (ISIS) who drove into the city and occupied the provincial government headquarters June 11.
Initially, the troops controlled the compound without clashes but later fierce clashes erupted between the troops backed by air support and the militants in four nearby villages and the al-Qadsiyah district, the source said.
A woman was killed and two others were wounded in the air-strike, while two university teachers were wounded by a mortar round which landed in the residential area inside the university compound, the source said.
The seizure of the university compound is a vital move by the security forces as it is the first foothold for the Iraqi troops in Tikrit, the source added.
Salahudin province is a Sunni-dominated province and its capital Tikrit is the hometown of former Iraqi leader Saddam Hussein.
Over 40 nurses from south Indian state of Kerala have been stranded for over two weeks in Tikrit teaching hospital since past two weeks.
Suicide bomber kills 19 in Shiite area of Baghdad
A suicide bomber killed at least 19 people at a market in the predominantly Shiite Muslim Baghdad neighbourhood of Kadhimiyah on Thursday, officials said.
The blast, which wounded dozens more, struck at about 2000IST (1530 GMT) in the Bab al-Darwaza market in Kadhimiyah, a northern area home to the shrine of a revered Shiite figure.
PTI & IANS