KABUL, Afghanistan - British troops pulled out of a troubled district in southern Afghanistan on Tuesday, while a U.S.-led coalition airstrike killed a suspected midlevel Taliban commander and up to 15 other militants, NATO said. NATO also said it was launching a new countrywide military operation with Afghan forces to maintain pressure on the Taliban over the fall and winter, and pave the way for long-promised development after the bitterest fighting in five years. Mark Laity, a NATO spokesman in Kabul, said the decision to withdraw the British troops from Helmand province's Musa Qala district follows an agreement with tribal...