15 Killed in Gunmen Attack at the Kenyan University.

At least 15 people have been killed by gunmen who attacked a Kenyan university Thursday, the Kenyan Interior Ministry said. 

As many as 550 others are unaccounted for at the campus that had about 815 students.

The Kenyan Red Cross said at least 50 students have been freed.

Security and ministry officials, in Kenya, said one terrorist was arrested as he tried to slip through the security cordon and flee the scene.

Kenyan forces cleared three of four dormitories and had cornered the militants in the last one, the Interior Ministry said.

Garissa is about 145 kilometers (90 miles) from the border with Somalia. Al-Shabaab militants have often launched attacks inside Kenya ever since the Kenyan government sent troops across the border to fight the group.

Assailants forced their way onto the campus by shooting at guards at the front gates, Kenya National Police said.

From there, attackers moved into a nearby girls' hostel, the Red Cross said. 

It's not clear how many gunmen were on campus. 

"We don't know how many there were, but there are probably more than 10," said Robert Alai Onyango, a blogger in Nairobi. "We believe the attackers were wearing something close to military fatigues." 

Onyango said the attackers appeared to be shooting indiscriminately and "basically from all angles." 

"They surrounded the mosque ... we don't know why they were surrounding the mosque," Onyango said. 

About 300 students who escaped sought refuge at a Kenya Defense Forces camp, local newspaper journalist Steven Astariko said.