Gunmen raided a Kenya university before dawn Thursday, firing indiscriminately and taking hostages.
At least 30 people were hospitalized from the attack at Garissa University College, the Kenyan Red Cross said. Local media reported varying death tolls, but CNN was unable to confirm the exact count.
The Somali-based Al Shabaab militant group claimed responsibility.
By 11 a.m. local time (4 a.m. ET), six hours after the attack began, the fight to regain control of the university continued. 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 .
Waking up to terror
The gunshots started going off "like fireworks" around 5 a.m., at the time of morning prayers, witness Milka Ndung'u told CNN affiliate NTV. She and others escaped to a field, but gunshots followed them.
Augustine Alanga told CNN he woke up to the sound of gunfire and described students running around, seeking safety.
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 university sought refuge at a Kenya Defense Forces camp, local newspaper journalist Steven Astariko said.
"We are saddened & angered by today's terrorist attack @ #Garissa Univ.," the U.S. Embassy in Nairobi tweeted. "Our deepest condolences 2 family/friends of victims."