Afghanistan plane crash kills 7 Americans By Holly Yan and Dave Alsup, CNN April 30, 2013 -- Updated 0839 GMT (1639 HKT) NEW: The Taliban claim responsibility, but the claim can't be verified immediately National Airlines: All 7 were crew members; there were no passengers National specializes in moving freight for the military and businesses The flight was en route from Bagram Air Base in Afghanistan to Dubai (CNN) -- A cargo plane crashed in Afghanistan killing all seven crew members on board Monday. All seven were U.S. citizens, the cargo carrier National Airlines said. The crash happened shortly after takeoff from Bagram Air Base in Afghanistan, the U.S.-based company said. The Boeing 747-400 was en route to Dubai, United Arab Emirates. "This was a purely cargo flight and no passengers were aboard," a company statement said. Cargo consisted of vehicles and routine general cargo. National specializes in moving freight for the military and businesses, as well as charter passenger service in the Middle East. The cause of the crash has not been determined. But Taliban spokesman Zabiullah Mujahid said his group shot down the aircraft and that "several foreign soldiers were killed." That claim could not be immediately verified. But in the past, the Taliban has exaggerated casualty figures. "This is a devastating loss for our family and we'll work diligently with authorities to find the cause," National Airlines President Glen Joerger said in the statement. Our focus at this time is on the family members of those we've lost, and on assisting the NTSB (National Transportation Safety Board) and Afghanistan Civil Aviation Authority in their investigations.