Taliban envoys are in discussions with America to free two captive Western professors in return for as many as 100 imprisoned militants, as part of a trust-building prisoner swap to spur a tentative peace process.

Kevin King and Timothy Weeks were seized at gunpoint in 2016 from Kabul and their fate is understood to have become a key issue in early discussions with US government officials.

The insurgent movement sent its most senior delegation yet for three days of talks in Abu Dhabi this week with the negotiating team including the chief of staff of the Taliban leader himself.

The talks are understood to have covered future of the 17-year-long American military presence in Afghanistan, as well as a suggested three month ceasefire.

But a Taliban source said discussions with Zalmay Khalilzad, Donald Trump’s peace envoy to Afghanistan, also included America’s desire to see Mr King and Mr Weeks freed.

The source said the militants were in turn drawing up a list of 100 fighters they wanted freed, expected to be headed by Anas Haqqani. The brother of Taliban’s military leader, Sirajuddin Haqqani, was captured in 2014. Afghan soldiers held by the Taliban will also be included in any swap.

Mr King, an American, and Mr Weeks, from Australia, were teaching at Kabul’s American University of Afghanistan (AUAF) before gunmen took them hostage near the campus in August 2016.

The Taliban source said: “In trust-building measures, the Taliban will give a list of 100 Taliban prisoners. In return Taliban will free prisoners including Afghan soldiers and two professors of Kabul American university.”

America has previously swapped senior Taliban captives to secure the release of US hostages. America’s only prisoner of war from the Afghan conflict, Sgt Bowe Bergdahl, was freed from insurgent captivity in 2014 in return for five senior Taliban figures held in Guantanamo Bay.