Nairobi: At least six persons were killed and several others injured on Friday when Al-Shabaab ambushed two buses in Kenya's Mandera county near the Somalia border. The two buses were heading to Mandera town from Nairobi when the militants sprayed bullets on the buses in Elwak, Xinhua news agency reported. "Preliminary investigations indicate that at least six persons were killed and several others injured when suspected Al-Shabaab fighters attacked two passenger buses this morning. We will provide more details later," officials said. The latest incident comes after the authorities called on non-locals living in Mandera not to travel by a bus until the end of Ramadan due to security threats posed by Al-Shabaab militants.