North Korea appeared to use a Chinese truck originally sold for hauling timber to transport and erect a ballistic missile that was successfully launched on Tuesday, highlighting the challenge of enforcing sanctions to curb its weapons program.North Korea state television showed a large truck painted in military camouflage carrying the missile. It was identical to one a U.N. sanctions panel has said was "most likely" converted from a Chinese timber truck.Since 2006, U.N. sanctions have banned the shipment of military hardware to North Korea. But control of equipment and vehicles that have "dual-use" military and civilian applications has been far less stringent.The vehicle was imported from China and declared for civilian use by the North Korean foreign ministry, according to a 2013 report by the U.N. panel. Tuesday's launch was the first time the truck had been seen in a military field operation in pictures published in state media.