According to the sources, the talks were held in a “focused and frank” manner, and the two sides reached an understanding on matters concerning Tehreek-e-Taliban Pakistan (TTP) and Islamic State.
They said negotiators called for the Taliban to designate the TTP as a terrorist organisation, while Pakistan would acknowledge the presence of Islamic State within its territory.
Sources added that representatives close to both sides have finalised a draft agreement, though the text has not yet been made available.
Despite a general understanding, differences remain over formally recognising the TTP as a terrorist group.
It remains unclear whether the Taliban administration will accept the outcome of the informal talks, although earlier reports indicated the delegations were approved by both the Taliban and Pakistan.
In previous formal negotiations held in Doha, Istanbul, Riyadh and Urumqi, the Taliban had rejected similar demands from Pakistan regarding the TTP.
Sources had earlier confirmed that figures close to the Taliban administration and the Pakistani government were engaged in discussions in Istanbul to explore ways of resolving disputes.
They said this was the first time the Taliban had agreed to allow a “non-Taliban” delegation to negotiate on Afghanistan-related issues.
Earlier, multiple sources said the Istanbul meeting was held with the approval of both the Taliban administration and Pakistan, and with the support of Türkiye.
The agenda included the activities of the TTP and Islamic State, border clashes, Pakistani air and ground strikes, economic conditions and the issue of migrants.
Previous rounds of formal talks between the Taliban administration and Pakistan in Doha, Istanbul, Riyadh and Urumqi had failed to produce results.