Kenya has marked the first anniversary of the Garissa University attack in which more than 148 people, most of them students, died at the hands of extremist gunmen.

Hundreds gathered at the Garissa University in eastern Kenya on Saturday to remember the incident, one of the country's worst-ever terrorist attacks.

Four gunmen from the al-Qaida-allied Somali al-Shabab group attacked the university, vowing retribution for Kenya's military support for Somalia's weak government.

Kenya has suffered a wave of extremist attack since it deployed the troops to Somalia in October 2011.

The university re-opened in January after extensive refurbishment of the bullet-scarred structures.

Adan Duale, the leader of the parliamentary majority, said at the event that Kenyan troops will remain in Somalia until their mission of pacifying the country is fulfilled.