Two homicide attackers bombed an Islamic university in the Pakistani capital Tuesday, killing four people and wounding 18 as the army pressed ahead with a critical offensive on a Taliban stronghold near Afghanistan, authorities said.

The near simultaneous blasts hit a women's cafeteria and a faculty building at Islamabad's International Islamic University. Its president said he suspected militants were responsible.

The blasts follow a string of bloody militant attacks around the country in recent weeks and amid warnings of more triggered by the start of the assault on South Waziristan tribal region four days ago. Several educational institutions were shut down over the past two days due to reported security threats.

SLIDESHOW: Homicide Bombers Attack Pakistani University

"It seems that (militant) sympathizers or collaborators are doing this to divert attention from the military operation," university president Dr. Anwar Hussain Siddiqui told The Associated Press. "They are trying to create panic in the capital city."

The university's sprawling campus on the outskirts of the capital, has more than 18,000 students, nearly half of them women. Many of the students come from abroad, including around 700 from China. It is a seat of Islamic learning, but most of the students take secular subjects such as management science or computer studies, Siddiqui said.

No group claimed responsibility for Tuesday's attacks.

The blast at the cafeteria left bits of flesh splattered on the floor. The second attack took place in the Islamic law department. TV footage showed a woman with a bloodied left leg being carried away a stretcher and a red brick building with shattered windows.

Interior Minister Rehman Malik said four people died and 18 were wounded, he said. The two attackers also died.

The army's offensive in South Waziristan pits some 30,000 troops against 10,000 militants. The army has conducted three smaller scale offensives in South Waziristan since 2004, all unsuccessful.

The military said Tuesday that troops backed by aerial bombing were steadily advancing on three fronts, meeting some stiff resistance.

Firefights raged in the areas around Kaskai and Shisanwam, and four more soldiers were killed, bringing the army's death toll over four days to 13, an army statement said. It added that 12 militants were killed, bringing the insurgent death toll to 90.

It is nearly impossible to verify independently the information because access to the region is blocked.

In an interview with The AP on Tuesday, army spokesman Maj. Gen. Athar Abbas said there was no evidence militants were trying to flee the battlezone.

"This is a mountainous terrain, therefore the operations tend to be slow," he said. "They are very determined to fight. So far we have been facing stiff resistance."

As many as 150,000 civilians — possibly more — have left South Waziristan in recent months. Authorities say that up to 200,000 people may flee in the coming weeks, but don't expect to have to house them in camps because most have relatives in the region.