The Afghan government Monday demanded that the United States provide proof that the country's largest private airline is involved in smuggling drugs or pay it compensation.
The US military barred Kam Air from its list of potential contractors after accusing it of transporting large amounts of opium into neighbouring Tajikistan, the Wall Street Journal reported on Friday.
The airline denied the allegation and Afghanistan's cabinet backed its call for compensation if the charges are not proven, describing the airing of the allegation in the media as "irresponsible".
"The US military should have informed the Afghan government first with evidence and documents, before notifying the media," a statement from the president's office said.
"The Afghan government has demanded that the US embassy deliver any evidence regarding the charges. The US embassy (has) so far failed to deliver any evidence.
"If it is not proven, the government of Afghanistan asks for restoration of legal dignity and compensation to Kam Air airline," the statement said.
The allegations by US military officials state that Kam Air ferried "bulk" quantities of opium -- the key ingredient in heroin -- on civilian flights, the Wall Street Journal newspaper said.
The US discovered the alleged drug smuggling when it started scrutinising Kam Air after the airline sought a US contract, Richard Longo, the commander of Task Force 2010, a coalition anti-corruption unit, told the WSJ.
Afghanistan produces about 90 percent of the world's opium and last year the United Nations Office on Drugs and Crime (UNODC) warned that opium cultivation in the country had increased by 18 percent.
Poppy farmers are taxed by Taliban militants who use the cash to help fund their insurgency against the government and NATO forces, UNODC said.
The poppies, which provide rich pickings in one of the world's poorest countries, also play a large part in the corruption that plagues Afghan life at every level, from district to national government.