Four aid workers kidnapped in northern Afghanistan last month have been freed by coalition forces, officials say. British nutritionist Helen Johnston, Kenyan medic Moragwa Oirere and two Afghans were rescued in Badakhshan province on Friday after being captured on 22 May, the Nato-led Isaf said. UK Prime Minister David Cameron called it an "extraordinarily brave, breathtaking" operation. Five hostage takers were killed during the rescue, Nato said The group - all employees of Switzerland-based aid group Medair - were making their way on horseback to the remote, mountainous province of Badakhshan, in north-eastern Afghanistan, when they were captured. A fifth...