UPDATE 1-Two Afghan Taliban shadow governors killed as air strikes step up

Afghan security forces, backed by U.S. air strikes, killed two of the movement's shadow provincial governors on Sunday, as fighting stepped up in the wake of the collapse of talks aimed at ending the conflict, officials said.The operations, launched on Saturday night, were aimed at foiling attacks planned by the Taliban on Afghan forces, said a senior security official in the capital Kabul, adding that clashes have escalated following the collapse of diplomatic talks between the United States an