He became the US Special Envoy for Afghanistan Reconciliation in 2018.

Khalilzad led the talks with the Taliban in Qatar that resulted in the Doha agreement with the Trump administration to fully withdraw US troops by May 2021.

He signed a peace deal with the Taliban after lengthy talks in 2020, in an agreement based on US forces leaving Afghanistan, reports Tolo News.

Khalizad quit his position on Wednesday.

Reacting to his decision, former intelligence chief Rahmatullah Nabil tweeted: "Finally, this con man was expelled from the scene after dragging Afghanistan into an irreversible catastrophe!"

Former Afghan foreign minister Rangin Dadfar Spanta criticised the US official and tweeted, "Khalilzad completed his destructive role in a shameful process. In this process, he had the support of some naive politicians and chauvinist circles. Now, we are confronted with a bunch of violent anti-civilised hurdles."

Khalilzad served under Presidents Donald Trump and Joe Biden as the Special Representative for Afghanistan Reconciliation.

A diplomatic veteran who is well-known in foreign policy circles, Khalilzad has also served as a US ambassador to Iraq and the United Nations.