Kabul - (AFP) - The Taliban on Monday released a former American soldier who had been detained in Afghanistan since 2020 in exchange for handing over an important ally of the movement who had spent 17 years in US prisons on charges of heroin trafficking.

Marc Frericks was working as a civil engineer on construction projects in Afghanistan when he was "taken hostage," according to Washington earlier.

"After long negotiations, American citizen Mark Frerex was handed over to an American mission, and this mission in turn handed us (Bashir Noorzai) today (Monday) at Kabul airport," Afghan Foreign Minister Amir Khan Mottaki said during a press conference in the capital, Kabul.

"We are very happy because we witnessed at Kabul International Airport in the Afghan capital the wonderful ceremony of the return of one of our compatriots," he added.

Noorzai received a hero's welcome from the government of the "Islamic Emirate of Afghanistan". Pictures showed him being greeted with wreaths of flowers by masked Taliban soldiers.

"If the Islamic Emirate of Afghanistan had not shown its strong determination, I would not be here today," Noorzai told reporters.

"My release in exchange for an American will be a source of peace between Afghanistan and the Americans," he added.

Noorzai is the second Afghan prisoner released by the United States in recent months. In June, Washington released Assadullah Harun after 15 years in Guantanamo.

Haroun was accused of being linked to al-Qaeda, but he spent years in the American detention center located in Cuba without formal charges being brought against him, after he was arrested in 2006 when he was a honey merchant.

He was not released under an agreement with the Taliban.

Afghan security analyst Hikmatullah Hikmat said that Noorzai's release represented an "important achievement" for the new rulers of Kabul.

"The Taliban can tell its soldiers and the Afghans that they can return people detained by opposition groups," he told AFP.

Mottaki said that Noorzai's return marked the beginning of a "new chapter" in relations between Afghanistan and the United States.

The Taliban seized power in Afghanistan just over a year before the United States and its NATO allies withdrew from the country after a 20-year military intervention.

Since then, the country has plunged into mounting economic and humanitarian difficulties, while Washington has frozen billions in Afghan assets abroad, with international support greatly diminished.

No country has yet recognized the new government, while Washington has repeatedly stressed that the Taliban must act in a way that makes them "deserving" of legitimacy.

The US State Department had previously described Frerex's release as one of the government's "fundamental and non-negotiable priorities".

US President Joe Biden said in a statement in January that "the Taliban must immediately release Mark before they can expect any reflection on their aspirations for legitimacy. This is not up for negotiation."

Noorzai, a militia leader with links to the Taliban, was sentenced to life in prison for heroin trafficking. He has been imprisoned so far for 17 years.

He was a fighter in the ranks of the "Mujahideen" who were supported by the United States against the Soviet occupation of Afghanistan and was close to the late founder of the Taliban, Mullah Omar.

During his trial, US prosecutors said he ran a "global drug network" and supported the first Taliban regime between 1996 and 2001.

While he did not hold an official position, "(Noorzai) provided strong support, including weapons," to the Taliban in the 1990s, according to what the movement's spokesman, Zabihullah Mujahid, told AFP on Monday.