Insurgents have killed 16 policemen in Afghanistan in the space of one day and beheaded eight of them, officials said Wednesday, as security forces prepare to guard a second-round election. Villagers in the southern province of Zabul Tuesday found the decapitated bodies of eight local policemen who were seized two weeks ago, deputy provincial governor Mohammad Jan Rassoulyar told AFP. The policemen were snatched by militants after an attack on their convoy. "Their bodies were discovered in Nawbahar district and we have sent elders to bring them to Qalat (the provincial capital)," he said, adding they were beheaded on Tuesday and found soon afterwards. The deputy police chief of Zabul, Ghulam Jilani Farahi, said the policemen were first shot and then decapitated. Taliban militants, who are responsible for many attacks on Afghan police, were not immediately available to comment. Also on Tuesday at least eight policemen were killed when Taliban fighters stormed checkpoints in the northern province of Badakhshan, said Gul Mohammad Bedar, the deputy provincial governor. "The Taliban attacked from the surrounding mountains with rockets and small arms. Eight police were killed after they ran out of ammunition," he said. "We have sent reinforcements and ammunition to help around 40 other police who are still in Yamgan district." Deputy provincial police chief Abdul Qadir Sayad confirmed the attack, saying 13 Taliban were also killed. The Taliban claimed responsibility and said they had taken control of the remote district. Afghanistan is in the middle of a presidential election, with former foreign minister Abdullah Abdullah and ex-World Bank economist Ashraf Ghani due to compete in a run-off vote on June 14. Providing security for the election will be a key test for around 350,000 Afghan police and soldiers who have taken over full responsibility from NATO combat troops. Afghan forces were praised for preventing major attacks in the first round of the election.