A California man who was captured fighting for the Taliban in Afghanistan in November 2001 has been released from prison, U.S. media report.
The federal Bureau of Prisons said that John Walker Lindh, known as the American Taliban, was released on May 23 from a high-security prison in Indiana, according to the AP news agency.
Lindh, 38, was set to be freed three years early for good behavior in a 20-year sentence.
The man converted to Islam at 16 and joined the Taliban in mid-2001. After the United States invaded Afghanistan following the September 11, 2001, attacks, he was one of hundreds of Taliban fighters captured on November 25, 2001.
Lindh is still "threatening the United States of America and still committed to the very jihad that he engaged in that killed a great American and a great CIA officer," Secretary of State Mike Pompeo said ahead of the release.
"There is something deeply troubling and wrong about this," Pompeo said on Fox News.
On the eve of Lindh's release, U.S. television station KNBC said it had received letters from him during his imprisonment in which he allegedly praised the Islamic State extremist group and called himself a political prisoner.
It was unclear why the letters, dating back to 2014-15, only came to light now.
Lindh, who gained Irish citizenship while in prison, cannot obtain a passport or travel abroad.
Lindh's release underscores the fact that, almost two decades later, the U.S. war against the Taliban continues.
Veteran U.S. diplomat Zalmay Khalilzad has been conducting several rounds of peace talks with the militants.
But the Taliban refuses to speak to the government in Kabul and has not renounced violence.
Khalilzad on May 22 briefed U.S. lawmakers in Washington on the progress of the talks.
The meeting was classified, but media reports suggested that the results of Khalilzad's efforts were met with skepticism on Capitol Hill.
Based on reporting by AP and AFP