Syrian rebels posted video on the internet Tuesday showing a government helicopter struck by a projectile that appears to be a surface-to-air missile. The video and another one that shows what looks like the same helicopter a few moments later suggests the rebels\' capacity to attack aircraft has advanced, The New York Times reported. Rebels have captured portable antiaircraft missiles or Manpads from the government and may also have received some smuggled into Syria, the newspaper said. Western countries have considered supplying them to the rebels. The missiles, supplied by the United States, helped Afghan rebels overcome the Soviet-backed government in the 1980s. Many of those same rebels then turned on the United States. \"Once these weapons are outside of government control, it is often extremely difficult to track their movement and control who has access to them,\" Matthew Schroeder, an expert on missile proliferation at the Federation of American Scientists in Washington, told the Times.