Kenyan police officers take cover outside the Garissa University College during an attack by gunmen in Garissa, Kenya, April 2, 2015. [Photo/IC]

GARISSA, Kenya - At least 15 people have been confirmed dead and 65 others injured after gunmen stormed a university in northeast Kenya early Thursday.

Kenya's Majority Leader of National Assemby Adan Duale confirmed the death toll, saying major security operation was still underway to rescue more students who were still trapped inside the university.

"Death toll has risen to 15, and we have 65 people injured," said Duale, who is at the scene with senior government and security officials.

Somali militant group Al-Shabaab has reportedly claimed responsibility for the attack.

"We have killed many people and Kenyans will be shocked when they get inside," they said in their radio station.

Internal security ministry said the Moi University campus in Garissa has been secured and attacks cornered as rescue mission continues. The ministry said three out of four hostels have been evacuated as attackers are in one hostel.

The heavily armed assailants forced their way into the university at about 5:30 a.m. local time and gained entry into student hostels after firing at guards manning the main gate.

Kenya Red Cross Society (KRCS) said the attack was preceded by an explosion at the university's gate. The number of student hostages is unknown, but 50 of them have been safely freed, it said.