Interim government forces in Libya have captured the university area of Sirte and fought their way into the city's Ouagadougou conference centre. A National Transitional Council (NTC) commander said some fighting continued at the sprawling conference complex. NTC forces launched the latest assault on Friday against Sirte, home town of fugitive leader Col Muammar Gaddafi. Once Sirte falls, the NTC say they will declare national liberation, even if Col Gaddafi remains on the run. The conference centre and university campus, as well as an apartment complex, saw particularly fierce resistance to the advance into Sirte. On Sunday afternoon, NTC fighters said they had captured the main hospital in Sirte. Several people suspected of being Gaddafi loyalists were taken into custody. The hospital has no electricity or water, and a handful of medical students and nurses were the only medical staff, the Associated Press reports. Thousands of civilians are said to remain trapped in Sirte, many of them fearful of retaliation by NTC forces. Pro-Gaddafi forces also control the desert enclave of Bani Walid, but it is seen as less significant as it does not lead to any exit routes from the country. 'Many snipers' NTC fighters came up against heavy weapons including tanks and artillery in Sirte on Friday and Saturday. "We have made good progress," NTC brigade commander Mahmoud Bayu told Reuters news agency. "We have entered the Ouagadougou centre, there is some fighting going on, but it's under our control." The commander's assertion that the complex was under NTC control could not be verified independently. Another commander, Nasser Zamud, told AFP the fighting in the university area had been "difficult" with NTC forces facing "a lot of snipers". Video showed one injured fighter at the campus hobbling after his comrades with a crutch in one hand and a Kalashnikov assault rifle in the other. On Friday, NTC forces launched what they called a final assault on Sirte, pushing pro-Gaddafi fighters back from their positions and towards the city centre. But on Saturday, their rapid advance slowed down as they fought street by street to take control of the city, Libya's symbolic second capital under Col Gaddafi. By the end of the day, they had taken control of a key boulevard which connects the Ouagadougou centre to the city centre. Civilians continued to leave Sirte on foot and by car over the weekend. NTC forces stopped and searched them at checkpoints. On Thursday, Col Gaddafi delivered an audio message urging Libyans to take to the streets "in their millions" to resist the interim leaders.