The security chief at Kabul airport has accused Afghan officials of colluding with drug smugglers and ordering the release of arrested suspects.
Gen Amarkhel says he receives death threats but will not give in
Gen Aminullah Amarkhel told the BBC interior ministry officials released two heroin smugglers caught red-handed.
The ministry said the suspects were freed because the packages they carried were not examined in enough detail.
Separately, the transport minister admitted the national airline, Ariana, was being used by drug smugglers.
Afghanistan is the largest producer of opium in the world, accounting for almost 90% of supplies.
The international community has spent millions of dollars on drug eradication since 2001, when the Taleban was ousted. However, although area under cultivation has dropped recently, output has not reduced significantly.
'Late at night'
The airport security chief, Gen Amarkhel, said: "We arrested a group of this [drugs] mafia - one of them was a member of the Ariana Afghan Airline's technical team. With him we arrested two females red-handed with 5kg of heroin which they wanted to take to India."
He said "smugglers" then called him saying one of the women would be released that night.
"The following day they called us again to say she had been released," Gen Amarkhel said.
"Surely the smugglers had their own people within the government because they told us in advance that their people would be released."
Security chiefs say Kabul airport needs better detection equipment
The head of the ministry of interior's counter narcotics team, Maj Gen Sayed Kamal Sadat, admitted the suspects were released.
"Prosecutors of the interior ministry released two female suspects because a detailed examination of the contents of the material caught did not exist," Gen Sadat said.
"It was also very late at night and the prosecutors decided to release them for one night."
He said the pair were rearrested the following day and that he was "going to interrogate them personally".
But Gen Amarkhel was not satisfied and said he did not understand why suspects in possession of 5kg of heroin could go free.
"It is not a good enough reason to say it was late at night," he said.
Gen Amarkhel said his team had been working to arrest a bigger group of suspected smugglers linked to the same group.
The popular destinations for drugs are Dubai and Delhi
But the woman who was released "leaked everything to the big group. As a result they all escaped to Pakistan".
Gen Amarkhel played a videotape in his office - which was also aired on a private Afghan TV station - in which he was challenged by a woman who, he said, was one of those released.
In the tape the woman tells him: "Do not touch me and do not touch the drugs. If I make one phone call I can fire you from your position."
The general asks who she would call.
"They are powerful people. They are higher than you in the government," the woman in the tape responds.
Kabul airport has X-ray machines to search both incoming and outgoing luggage.
The interior ministry says the smuggling situation is improving
But Gen Amarkhel said the airport needed more sophisticated equipment and more X-ray machines to detect drugs more effectively.
He has been the security chief for the past seven months.
"During this time I have arrested 13 foreigners and have seized about 30kg of heroin... I have also arrested six Afghans," Gen Amarkhel said.
The two main destinations for drug smugglers are Dubai and Delhi, he says.
Gen Amarkhel says he has been issued death threats in telephone calls
"But I will not give in to these people," he says.
A number of high-ranking government officials have told the BBC there is a culture of impunity in drug smuggling and that the government is partly to blame.
One high ranking official, who did not want to be named, said: "It is embarrassing to know that our government has evidence against some officials but still does not arrest them".
Last year, Interior Minister Ali Ahmad Jalali resigned, saying he wanted to pursue his academic studies.
But government insiders said he quit because he wanted to be tough on drug dealers, especially those within the government, but this had not proven possible.
Afghanistan's transport minister, Enayatullah Qasemi, told the BBC that the drug smuggling situation was getting better, although he admitted the Ariana airline still faced difficulties.
"The situation has improved from a year ago [in terms of the amount of drugs being carried on Ariana], but still we have major problems," he said.
"We are obviously concerned, it affects our reputation," Mr Qasemi said.
"We are taking all the measures that we can to try to ensure our planes are not carrying drugs."