ISLAMABAD (AFP) - Taleban co-founder Mullah Baradar was due in Pakistan on Wednesday (Oct 2) to hold talks with officials, the militant group's spokesman said, as unconfirmed reports suggested US envoy Zalmay Khalilzad was already in Islamabad.

If so, it could provide the first known opportunity for the two to meet since US President Donald Trump last month abruptly scuttled talks with the Taleban that were seeking a way for Washington to exit its longest war.

Insurgent spokesman Zabihullah Mujahid tweeted that the Pakistan visit will be the fourth leg of a tour that included Russia, China and Iran.

Baradar is head of the Taleban's political wing and usually based in Qatar, where for nearly a year the insurgents held face-to-face meetings with a US delegation led by Khalilzad.

The two sides were on the brink of a deal that would have seen Washington begin withdrawing troops from Afghanistan in return for various security promises from the Taleban.

On Sept 7, however, Trump called off a top-secret summit due to be held between the US and the Taleban at Camp David and declared the talks "dead" two days later.

The Taleban threatened more violence, but both the insurgents and the US left the door open for negotiations to resume - with most experts agreeing Washington will have to return to the table eventually.

Dawn, Pakistan's largest English-language daily, reported that Khalilzad had arrived in Islamabad on Tuesday, although it did not give a source. There was no immediate confirmation from the Pakistani Foreign Office or the US embassies in Islamabad or Kabul.

A senior Taleban source in Pakistan told AFP that the group was aware of Khalilzad's visit and was ready to meet him.

"We have not backtracked from talks," the source added. "It was America who backtracked." Another senior Taleban militant said it would be "up to Mullah Baradar, who is leading the delegation, to decide whom they would like to talk to".