A police official says masked gunmen have stormed a university campus in Garissa Town in eastern Kenya.

Musa Yego says gunshots and explosions can be heard from a building on the campus, which is surrounded by police and military.

It was not immediately clear if there were any fatalities or injured.

Kenya's northern and eastern regions, which border Somalia, have been most affected by attacks blamed on al-Qaida-linked al-Shabab Islamists from Somalia. They have vowed retribution against Kenya for sending its troops to Somalia.