MOSCOW — In a setback to the escalating U.S. military efforts in Afghanistan , the president of Kyrgyzstan said Tuesday that his government will shut down the American air base in his country. U.S. officials say that the Manas Air Base is vital to plans to send an additional 30,000 American troops to Afghanistan , a linchpin of President Barack Obama's efforts to pacify the country. The announcement by President Kurmanbek Bakiyev came in Moscow , not in his own capital, and shortly after the Russian government reportedly agreed to lend Kyrgyzstan $2 billion , write off $180 million in...