Two children have been killed in a U.S. air strike in Afghanistan. The victims were watering fields in Afghanistan’s Kunar province when they came under attack. The deaths come just two weeks after nine Afghan boys were mistakenly killed by NATO gunships. Speaking in Washington, the U.S. commander in Afghanistan, General David Petraeus, touted the progress of U.S. military goals in Afghanistan but called them “fragile and reversible.”

Gen. David Petraeus: “It is ISAF’s [International Security Assistance Force] assessment that the momentum achieved by the Taliban in Afghanistan since 2005 has been arrested in much of the country and reversed in a number of important areas. However, while the security progress achieved over the past year is significant, it is also fragile and reversible.”

Petraeus went on to suggest a scenario under which U.S. troops would remain in Afghanistan beyond a 2014 withdrawal date through the operation of joint military bases with Afghan forces. Petraeus said, “It’s very important to stay engaged in a region in which we have such vital interests.”