Kenya police have arrested five people in connection with the terror attacks on Garissa University College, Interior Minister Joseph Nkaissery said.

In the attack on Thursday, 1 April, gunmen from militant group Al-Shabaab killed 147 people, including 142 students, three security officers and two university security officers.

Nkaissery told NTV that 104 more people had been injured in the attack, including 19 critically.

Horrifying accounts have emerged of the massacre on the campus, which is in eastern Kenya, near the border with Somalia.

The gunmen first targeted a prayer hall, killing some of the Christians praying there and taking others hostage.

Victims forced to call parents

The militants, who were wearing masks and carrying AK-47s, then moved through the campus and into the dormitories, shooting non-Muslims and sparing Muslims, according to witness accounts.

Some claimed that victims were made to call their parents and tell them to contact the Kenyan government and tell them to pull Kenyan troops out of Somalia before they were killed.

Student Japhet Mwala, who sleeping in a dorm when it was attacked, said "We were sleeping when we heard a loud explosion that was followed by gunshots, and everyone started running for safety," she told Agence France-Presse.

"There are those who were not able to leave the hostels where the gunmen headed and started firing. I am lucky to be alive because I jumped through the fence with other students," she said.

Some said they smeared themselves with blood and pretended to be dead.

After a 12-hour siege with Kenyan security forces, four gunmen were killed and one was reportedly arrested, after being found hiding beneath a bed.

The attack is the worst by the group in the country since the Westgate Mall attack in Nairobi in 2013, in which 67 were killed.