US and Taliban negotiators have agreed on a draft framework for a peace deal seeking to put an end to the 17-year conflict in Afghanistan, Washington's top negotiator has said.
Zalmay Khalilzad, the US Special Representative for Afghanistan Reconciliation, was in Kabul to brief the Afghan government about the talks.
In a New York Times interview, Mr Khalilzad said the Taliban had pledged not to give terrorist groups like al-Qaeda safe haven - a key demand from Washington if it pulls out troops.
"We have a draft of the framework that has to be fleshed out before it becomes an agreement," he told The New York Times in an interview, adding that as part of the proposed deal the Taliban would vow to prevent Afghanistan being used as a hub for terrorism.
US negotiators held six days of talks with the Taliban in Qatar last week.
"The Taliban have committed, to our satisfaction, to do what is necessary that would prevent Afghanistan from ever becoming a platform for international terrorist groups or individuals," he said.
Until the interview, the US envoy had only released a series of tweets about the talks - saying "significant progress" had been made but without providing details.
A senior Taliban official who attended the talks told the BBC over the weekend that both sides had agreed to form two committees to draw up detailed plans on how to implement agreements in principle on the two key issues: when US-led troops could be withdrawn from Afghanistan, and whether the Taliban would deny jihadist groups from using the country as a base.
The official, speaking on condition of anonymity, said the committees would "identify routes for the withdrawal, and how much time is needed. We suggested six months, but are flexible".
The discussions clearly remain at a provisional stage - and a long way from agreement on the broader issues required for lasting peace in Afghanistan - but after years of stalemate, it's welcome progress.
The Taliban ruled the country from 1996 until 2001 when the US invaded Afghanistan after al-Qaeda - which had used the country as a base - carried out the 9/11 attacks in the US.
They remain a top insurgent force in Afghanistan, with 17-year conflict causing between 6000 and 11,000 civilian deaths every year since 2009.
The Taliban's power and reach have surged since foreign combat troops left Afghanistan in 2014.
Thousands of Nato-led troops remain in training, support and counter-terrorism roles. The US has the largest contingent, with 14,000. US President Donald Trump is reportedly considering withdrawing half of these.
About 8000 troops from another 38 countries are also present.
Analysts say it could be years before a substantive peace deal is reached.
The Trump administration's strategy has been to put pressure on the Taliban to negotiate with the Afghan government.
It is exploring a full withdrawal of US troops in return for a ceasefire and a commitment by the Taliban to these direct talks.
The Taliban say they will only begin negotiations with the government once a firm date for troop withdrawal has been agreed.
Afghan president speaks out
Afghan President Ashraf Ghani, meanwhile, has made a new call for direct talks between the Afghan government and the Taliban, who have so far refused dismissing the government as "puppets".
Mr Ghani alluded to fears that freedoms could be lost if the Taliban were to share power. Women's rights activists have expressed particular concern due to the militants' brutal treatment of women when they ran the country.
"We are committed to ensuring peace," he said. "But there are values which are non-negotiable, for example national unity, national sovereignty, territorial integrity, a powerful and competent central government and basic rights of the citizens of the country."
According to Mr Ghani's office, Mr Khalilzad in a meeting on Sunday denied that there had been any discussions with the Taliban about future governance arrangements in Kabul.
On Friday, Mr Ghani said more than 45,000 members of the country's security forces had been killed since he became leader in 2014.
It is estimated about 15 million people - half the Afghan population - are living in areas either controlled by the Taliban or where the militants are openly present and regularly mount attacks.