NAIROBI:  A Kenyan official says suspected Islamic extremists killed two people when they shot at two vehicles in Kenya's northern Mandera town. North Eastern Regional Coordinator Mohamud Saleh said Monday that three people were wounded in the dawn attacks by gunmen believed to be Somalia's al-Shabab militants. He said the gunmen shot at a bus killing one passenger and wounding three others. Saleh says the rebels then shot at a truck following the bus and killed one passenger. Saleh said both drivers kept going after the shootings, preventing further loss of life and injury. Kenya has experienced a wave of retaliatory attacks by al-Shabab, which is linked to al-Qaida, since it sent troops to Somalia to fight the extremists in 2011.