The US military says four helicopter engines worth $13 million are missing in the Afghanistan-Pakistan region. US spokeswoman Lt. Col. Rumi Nielson-Green says the helicopters were being shipped overland from the US base in Bagram to a seaport for shipment back to Fort Bragg, North Carolina. She says the parts went missing sometime before the 101st Airborne's arrival in Afghanistan in April. Nielson-Green says the parts were being shipped by a Pakistani trucking company, but it is not clear where they disappeared. The US is not disclosing what kind of engines they were.