An American navy veteran detained in Afghanistan since 2020 was released by the Taliban on Monday in exchange for an ally who had spent 17 years in a US jail for heroin smuggling, Afghanistan's foreign minister said.

Mark Frerichs was working as a civil engineer on construction projects in Afghanistan when he was "taken hostage", Washington previously said.

"After long negotiations, US citizen Mark Frerichs was handed over to an American delegation and that delegation handed over (Bashar Noorzai) to us today at Kabul airport," Afghan Foreign Minister Amir Khan Muttaqi said at a press conference.

"We are happy that at Kabul International Airport, in the capital of Afghanistan, we witnessed the wonderful ceremony of one of our compatriots returning home."

Noorzai was welcomed with a hero's fanfare by the government of the newly styled Islamic Emirate of Afghanistan (IEA).

Photos show he was greeted by masked Taliban officials bearing floral garlands.

"If the IEA had not shown its strong determination, I would not have been here today," Noorzai told reporters at a press conference.

The Taliban seized power in Afghanistan a little over a year ago as the United States and their NATO allies withdrew from the country after 20 years of military intervention.

Since then, the nation has been further plunged into economic and humanitarian hardship, with billions in Afghan assets abroad frozen by Washington and international aid vastly reduced.

No country has yet to recognise the new government, with Washington repeatedly telling the Taliban that they will have to "earn" legitimacy.

'Non-negotiable'

The US state department had previously described the navy veteran's release as one of the government's "core, non-negotiable priorities".

"The Taliban must immediately release Mark before it can expect any consideration of its aspirations for legitimacy. This is not negotiable," US President Joe Biden said in a statement in January.

Noorzai, a warlord and Taliban associate, was sentenced to life imprisonment for heroin smuggling and had served 17 years.

He once fought with US-backed Mujahideen forces against the Soviet occupation of Afghanistan and was a close associate of the group's late founder Mullah Omar.

At the time of his trial, US prosecutors said he ran a "worldwide narcotics network" and supported the Taliban's first regime between 1996 and 2001.

"Today's sentence definitively puts an end to Noorzai's long criminal career," they said at the time.

While he held no official position, Noorzai had "provided strong support including weapons" for the Taliban in the 1990s, Afghanistan government spokesman Zabihullah Mujahid told AFP on Monday.

© Agence France-Presse