U.S. military investigators want to know whether members of the Afghan Air Force have been using American-financed aircraft to smuggle illicit drugs across the country. The military inquiry is being spearheaded by elements within International Security Forces-Afghanistan, and the U.S. Drug Enforcement Administration is leading a separate probe into the matter. The Wall Street Journal first reported about the inquiries late Wednesday. Army Lt. Gen. Daniel Bolger, commander of NATO Training Mission-Afghanistan, told the Journal that the investigations are in the preliminary stages and said no evidence of trafficking has been uncovered. "The nature of the allegations is fairly dramatic and indicated that [AAF officials] were transporting drugs on aircraft and transported weapons not owned by the government of Afghanistan for the use of private groups," he said. American investigators are also looking into whether the suspected smuggling ring was tied to the shooting of eight U.S. Air Force officers by an Afghan Air Force colonel last April in Kabul. At the time, Taliban forces claimed responsibility for the killings. But the slain American officers were part of an ongoing investigation into misuse of Afghan aircraft by indigenous military personnel, the Journal reported. The Afghan Air Force’s arsenal consists mainly of Russian-made Mi-17 cargo helicopters, along with a handful of Mi-25 attack helicopters used to support ground elements of the Afghan National Security Forces. The Air Force is the lead service in charge of training and equipping the AAF under the NATO Training Mission-Afghanistan. American air advisers and their Afghan counterparts are headquartered in Kabul. The majority of training operations are conducted at the Air Force’s facility in Shindand air base in western Afghanistan. The AAF played an instrumental role in the U.S. offensive into the Taliban stronghold of Marjah in 2010. Afghan airmen ferried ANSF troops and provided air cover for coalition forces during the battle, which kicked off President Obama’s surge strategy in Afghanistan that year.