Senior Taliban members met former Afghan President Hamid Karzai and top official Abdullah Abdullah in the capital Kabul Wednesday, according to the SITE monitoring group, as the group's senior leader ordered the release of "political detainees".

Abdullah had led the government's peace council during failed talks between the warring sides in Qatar. Karzai was the first Western-backed leader of the country after a US-led invasion toppled the Taliban in 2001 and remained in office until 2014.

Taliban leaders "have said that they pardoned all former government officials and thus there is no need for anyone to leave the country," SITE said, after the Taliban published images of Karzai meeting Taliban negotiator Anas Haqqani.

The head of the hardline group, Haibatullah Akhundzada, meanwhile ordered the release of "political detainees", the Taliban tweeted. 

"From tomorrow, all provincial governors must release all political detainees -- major and minor -- without any restrictions or conditions, and deliver them to their families," it said in Arabic.

The Taliban insisted Tuesday in their first press conference since seizing power at the weekend that they would not seek "revenge" and declared a general amnesty.

A government would soon be formed, spokesman Zabihullah Mujahid said, adding that the Taliban would "connect with all sides".

Former president Ashraf Ghani -- who succeeded Karzai in 2014 -- fled the country as the Taliban encircled Kabul, taking refuge in the United Arab Emirates.