"We can say that the university has been liberated," Maan Saadi, a major general in the Counter-Terrorism Service (CTS), told AFP.
The vast Mosul University campus, one of the biggest in Iraq, lies in the north of the city on the east bank of the Tigris River that splits Mosul in two.
"We have done the hardest part... we may recapture the entirety of the eastern side in the next 10 days or so," Saadi said.
The top CTS commander, General Taleb Sheghati al-Kenani, spoke to state-run Iraqiya TV from the university.
Signup to our newsletter and follow us on Facebook and Twitter!
Saadi estimated Iraqi forces had now recaptured 85 percent of the eastern side since the October 17 launch of a huge offensive to retake Mosul, the jihadists' main stronghold in the country.
The initial phase of the offensive saw a variety of forces retake significant swathes of land in little time but the going has been tough inside the city itself.
After a lull in operations, the CTS and other forces stepped up their coordination and, with increased air and advisory support from a US-led coalition, launched a fresh push just before the New Year.
Over the past two weeks, Iraqi forces have overrun several districts and reached the Tigris River.
The destruction of all bridges over the river in air strikes has made it difficult for IS fighters in east Mosul to resupply or escape to the west bank, which they still fully control.
The western side of Mosul, which is home to the old city and some of the jihadists' traditional bastions, was always tipped as likely to offer the most resistance.