Taliban officials said U.S. negotiators on Saturday agreed on a draft peace pact setting out the withdrawal of foreign troops from Afghanistan within 18 months, potentially ending the U.S.'s longest war. The details of the draft were given to Reuters by Taliban sources at the end of six days of talks with U.S. special peace envoy Zalmay Khalilzad in Qatar aimed at ending the war, more than 17 years since American-led forces invaded Afghanistan. It stipulates that troops would leave within 18 months of the agreement being signed.

While no joint statement was issued, Khalilzad tweeted later that the talks had made "significant progress" and would resume shortly, adding that he planned to travel to Afghanistan to meet government officials.

A Taliban statement issued later also noted progress on troop withdrawal and other issues but said more negotiations and internal consultations were required. "The policy of the Islamic Emirate during talks was very clear — until the issue of withdrawal of foreign forces from Afghanistan is agreed upon, progress in other issues is impossible," said Taliban spokesman Zabihullah Mujahid, using another name the group calls itself.

According to the sources, the hardline group gave assurances that Afghanistan will not be allowed to be used by al-Qaida and Daesh militants to attack the United States and its allies — a key early demand of Washington. They said the deal included a ceasefire provision but they had yet to confirm a timeline and would only open talks with Afghan representatives once a truce was implemented. Up until now, the Taliban has repeatedly rejected the Afghan government's offer of holding talks, preferring instead to talk directly to the U.S. side, which it regards as its main enemy.

Up until now, the Taliban has repeatedly rejected the Afghan government's offer of holding talks, preferring instead to talk directly to the U.S. side, which it regards as its main enemy. "In 18 months, if the foreign forces are withdrawn and ceasefire is implemented, then other aspects of the peace process can be put into action," a Taliban source said, quoting from a portion of the draft. More talks on the draft are expected in February, again in the Qatari capital Doha, the Taliban sources said. They expect their side to be led by new political chief Mullah Abdul Ghani Baradar, the movement's co-founder and a former military commander who was released from prison in Pakistan last year.