A Kenyan police official says a man has been shot dead after stabbing a policeman guarding the perimeter wall of the U.S. Embassy in Nairobi.

Vitalis Otieno, the officer in charge of the Gigiri area that hosts several embassies, says a pedestrian walking along the street stabbed the policeman on Thursday and attempted to take his gun.

Otieno says the identity of the attacker is known to police and says he is a Kenyan from the volatile region of Wajir.

The U.S. Embassy confirms there was a shooting and says no embassy personnel were involved.