The Afghan government has denied allegations that some officials in its U.S.-funded air force have been using military aircraft to ferry narcotics and illegal weapons around the country.
The Afghan Defense Ministry called the claims "baseless" in a statement Sunday.
The Wall Street Journal reported that U.S.-led NATO forces are investigating the allegations, which came from Afghan officers inside and outside the air force.
The newspaper said the inquiry is also exploring whether the alleged smuggling was connected to an incident in April in which an Afghan air force colonel gunned down eight U.S. Air Force officers at Kabul airport.
NATO declined to comment on the reported investigation.