Nairobi, Sha'ban 08, 1436, May 26, 2015, SPA -- At least 20 policemen were killed in an ambush by Somali militant group al-Shabaab in north-eastern Kenya, police said Tuesday. The militants bombed a five-vehicle convoy of Kenyan security forces headed for the village of Yumbis in Garissa county on Monday night, a police officer told dpa on condition of anonymity. "We still don't know how many people were killed ... several people are still missing," the officer said. The attack comes a week after al-Shaabab hit the villages of Yumbis, Welmareer and Damajale in Garissa county, but was soon repelled by the army and police. The militants returned to Yumbis on Monday night and seized the village, according to police. --SPA 12:10 LOCAL TIME 09:10 GMT www.spa.gov.sa/w