(CNN) –

Gunmen attacked a university in south central Kenya before dawn Thursday, firing indiscriminately and sending students scrambling for cover.

At least 30 people were hospitalized from the attack at Garissa University College, most of them with gunshot wounds, the Kenya Red Cross said.

Garissa is about 90 miles from the border with Somalia. And while no group immediately claimed responsibility for the attack, Al-Shabaab militants have often launched attacks inside Kenya from Somalia in the past since the Kenyan government sent in troops across the border to fight the group.

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 the dormitories seeking shelter.

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.”

The university was established in 2011 and is the only public university in the region. It has a staff of 75.

The college’s website doesn’t indicate how many students attend the institution, but reported two classes of more than 400 who enrolled in the first two years.

History of Al Shabab in Kenya

The deadliest attack by Al Shabaab in Kenya was in September 2013, when the group attacked the Westgate shopping center in Nairobi, killing 67 people.

Last month, the U.S. Embassy warned of possible attacks “throughout Kenya in the near-term” following the reported death of a a key al-Shabaab leader, Adan Garaar.

“Although there is no information about a specific location in Kenya for an attack, U.S. citizens are reminded that the potential for terrorism exists,” the warning said.