An eighth round of talks on a pact that would allow the United States to end its longest war and withdraw its troops from Afghanistan ended on Monday and both sides would consult their leaders on the next steps, the Taliban said.

The talks, held in Qatar since late last year between the Taliban and US officials, have brought hopes for an agreement allowing US troops to leave in exchange for a Taliban promise that Afghanistan will not be used by militants as a base from which to plot attacks abroad.

A Taliban spokesman, Zabihullah Mujahid, said the latest talks, which a US official said earlier involved technical details and the implementation mechanisms of a pact, ended early on Monday.

"It was long and useful, both sides decided to consult with their leaders/seniors for the next steps," Mujahid said in a statement.

US officials were not immediately available for comment but the chief US negotiator, veteran Afghan-American diplomat Zalmay Khalilzad, said on Sunday hard work was being done "toward a lasting and honourable peace agreement and a sovereign Afghanistan which poses no threat to any other country."

An agreement would allow US President Donald Trump to achieve his aim of ending a war launched in the days after the September 11, 2001, attacks on the United States.

The war has become a stalemate, with neither side able to defeat the other and casualties rising among civilians as well as combatants.

The pact is expected to include a Taliban commitment to hold power-sharing talks with the US-backed government but it is not expected to include a Taliban ceasefire with the government, leading to fears the insurgents will fight on when US forces leave.

President of the US-backed government, Ashraf Ghani, appeared to question the deal on Sunday, saying his nation would decide its future, not outsiders.

Ghani and his government have not been involved in the negotiations. The Taliban do not recognize the government and have refused to talk to it.

"Our future cannot be decided outside, whether in the capital cities of our friends or neighbours. The fate of Afghanistan will be decided here in Afghanistan," Ghani told a gathering for prayers marking the Eid al-Adha Muslim festival.

Khalilzad said scholars believed the deeper meaning of Eid was to sacrifice one's ego.

"Leaders on all sides of the war in Afghanistan must take this to heart as we strive for peace," he said.