The terrorists were killed during a joint police raid at around 2am in a house in Kwachocha, Malindi, in Kilifi County.
The raid followed a tip-off from the public, Malindi OCPD Matawa Muchangi said.
The police boss said the four were killed in a fierce gun fight after they reportedly declined to surrender and instead hurled a hand grenade at the police.
Issa Jabir Ali of Kisauni in Mombasa, born in 1987 in Ganjoni, Sirgoi, in Kilifi County was also among the slain terror suspects who was immediately identified by police.
Mr Muchangi said the four died on the spot while three others were suspected to have escaped with severe gunshot wounds and an AK-47 rifle.