U.S. President Barack Obama met privately with Defense Secretary Robert Gates and the commander of U.S. and NATO troops in Afghanistan, General David Petraeus, at the White House Monday, to discuss the U.S.-led military efforts in the war-torn country.The White House issued a statement saying the three discussed the effectiveness of the military surge, the growth of the Afghan National Security Forces and President Hamid Karzai’s expected March 21 announcement on beginning a transition to Afghan security taking the lead.The Oval Office meeting, which was closed to reporters, follows new tensions between Washington and Kabul over the accidental killing of nine Afghan boys during a coalition airstrike in northeastern Kunar province earlier this month.President Obama, Secretary Gates and General Petraeus apologized for the deaths, calling them a setback for relations with the Afghan people.Mr. Karzai accepted the apologies, but urged an end to civilian casualties – Voanews