Security forces in north-west Pakistan are battling militants inside a university in the town of Charsadda, with reports of several deaths.
Police said two gunmen had been killed but others were thought to be holding out in campus buildings at Bacha Khan University as shooting continued.
Some students have been rescued, Deputy Inspector General Saeed Wazir said. At least three people were injured.
More than 130 students were killed at a school in nearby Peshawar in 2014.
Charsadda is about 50km (30 miles) from the city.
It appears the attackers set off explosions when they stormed the university on Wednesday, at around 09:30 local time (04:30 GMT).
Police and soldiers, backed by armoured vehicles, surrounded the campus and an evacuation got under way.
An emergency official, Bilal Faizi, told AFP news agency he had seen five dead bodies, all with bullet wounds.
The report could not be verified independently.
More than 3,000 students and 600 visitors attending a poetry event were inside the university at the time of the attack, according to Pakistan's Geo News. Other reports suggest many of the students and staff had not yet arrived.
Bacha Khan is a new university, founded in 2012, its website says.
Just days ago, some schools in Peshawar were closed by the authorities amid reports that militants were planning an attack.