NAIROBI, Kenya (AP) — A Kenyan official says at least five police officers have been killed and three others wounded when their truck ran over a bomb near the Somalia border.

The attack took place Wednesday morning in Garissa County in Kenya's east, near the Liboi border crossing.

North Eastern regional coordinator Mohamud Saleh says the officers from the paramilitary wing of the police known as the General Service Unit had been out on patrol at the time.

No group has claimed responsibility for the attack, but suspicion has fallen on the Somalia-based extremist group al-Shabab. The al-Qaida-linked group has vowed retribution for Kenya's troop presence in Somalia.

Kenya sent troops to the Horn of Africa nation in 2011 to help bolster the country's weak government against al-Shabab's insurgency.