KANDAHAR (AFP) Taliban insurgents killed four Afghan policemen Saturday in two separate attacks in their spiritual heartland in southern Afghanistan, officials told AFP. Militants shot at a police vehicle in Khakrez district of Kandahar province, killing three policemen and wounding one, district governor Abdul Qayoum told AFP. Separately, militants riding a motorbike gunned down another policeman in Kandahar city on Saturday morning before escaping, deputy provincial police chief Mohammad Shah said. The policeman had been off-duty and was walking in civilian clothes near the city centre when he was assassinated, Shah said.