An Afghan freed after 15 years of detention in the United States' notorious Guantanamo Bay prison arrived home Saturday to a hero's welcome.

Asadullah Haroon had languished without charge for years at the US detention centre in Cuba after being arrested in 2006 while working as a honey trader travelling between Pakistan and Afghanistan.

Washington accused him of being a courier linked to Al-Qaeda and serving as a commander with the militant Hezb-e-Islami group.

Like most of the Guantanamo detainees he was never formally charged, and his lawyers filed numerous lawsuits over the years to press for his release.

"My first question is on what basis I was imprisoned in Guantanamo?" he told a media scrum on the tarmac at Kabul airport.

Earlier, officials had released pictures of him on a private jet coming from Qatar, accompanied by senior Taliban officials. 

"My family and relatives suffered," said Haroon, sporting a black Taliban-style turban and with green garlands wrapped around his neck.

Several giant banners of Haroon were strung up on lampposts on the main road leading from the airport.

US authorities faced accusations of torture and abuse against prisoners at Guantanamo, with some allegedly held in cages and subjected to illegal interrogation techniques.

"It wasn't the physical abuse, but the mental stress increased day by day," Haroon told reporters.

"We called it 'white torture'."

Celebrations 

Haroon's family celebrated Friday after hearing news of his release.

"It's like Eid in our house, like a wedding. These are very emotional moments for us," his brother Roman Khan told AFP from Peshawar in Pakistan, where the family live as refugees.

The family, who fled to Pakistan during the 1979 Soviet invasion of Afghanistan, have admitted Haroon was a Hezb-e-Islami member -- like many in their refugee camp -- but said he had no links with Al-Qaeda.

Haroon's release came after "direct and positive" interaction between the Taliban and Washington, Afghanistan government spokesman Zabihullah Mujahid said in a statement.

He said Haroon was one of two Afghan detainees remaining in Guantanamo Bay -- the other being Muhammad Rahim, accused by the CIA of being a close associate of Al-Qaeda founder Osama bin Laden.

Afghanistan's foreign ministry spokesman Abdul Qahar Balkhi said the government was "hopeful" that Rahim will also be freed soon.