At least six people were killed and 16 others were wounded in a suicide attack close to Marshal Fahim National Defense University in Kabul city on Thursday, Kabul police confirmed.

The attack took place at 12:10pm Kabul time at the entrance gate of Marshal Fahim National Defense University in Kabul's PD5, according to the officials.

Ministry of Interior said policemen at the gate recognized the suicide attacker and when a policeman was trying to unarm him and prevent him from entering the university, he detonated his explosives.

The ministry said four civilians are also among those wounded.

Eyewitnesses said the suicide bomber detonated his explosives among the cadets who were leaving the university. 

All those wounded have been transferred to hospitals, officials said. 

No group including the Taliban has claimed responsibility for the attack.