At least seven people have been killed, with a further 20 injured, in the terror attack on Bacha Khan University in northwestern Pakistan.

It's not yet clear how many of the dead are attackers and how many are civilians.

Gunfire and explosions were heard Wednesday morning local time from within Bacha Khan University in Charsadda, northwestern Pakistan.

There are still dead inside, and the operation is ongoing, Bilal Faizi, a local emergency service spokesman told CNN.

There have so far been no claims of responsibility.

Two of the university attackers have been killed by security forces, Saeed Khan Wazir, Deputy Inspector General (DIG) of Police, of the Mardan Range region told CNN.

There are fears that the remaining attacker or attackers are holding hostages within the campus grounds.

Pakistan Army soldiers have entered the university, according to Geo News, citing a reporter on the scene.

University faculty, administrative staff and students are in the university grounds. Five injured people have so far been evacuated from the campus, the report states, but none of the 3,000 students and 600 guests on the university campus have been injured, according to Pakistani media, citing an audio message released by Fazal Rahim Marwat, vice-chancellor of Bacha Khan University.

"Security forces are present on site and are combating the terrorists in a gunfight, but as yet are not sure how many terrorists are holed up inside the university," Geo News reported.

(CNN)