In Afghanistan, four policemen have been killed in three explosions which took place minutes apart in the southern city of Kandahar. Officials said the blasts took place yesterday evening near a convoy of troops travelling out of the city. Ten people were injured.Meanwhile, four Nato service members died in attacks around the country. Their nationalities were not released.Afghan and Nato-led forces are in a major operation in Kandahar province to drive out militants.The Afghan war is now in its bloodiest year since the 2001 US-led invasion that ousted the Taliban from power.