WASHINGTON(AFP) - A Malaysian airliner with 295 people on board was shot down over Ukraine by a surface-to-air missile Thursday but it was unclear who fired the weapon, US officials said.

US intelligence analysts "strongly believe" a surface-to-air missile downed the plane and are reviewing data to determine whether the weapon was launched by pro-Moscow separatists in Ukraine, Russian troops across the border or Ukrainian government forces, said a US official, who spoke on condition of anonymity.