US secretary of state John Kerry arrived in Kabul on Thursday to pressure feuding presidential candidates to resolve the disputed election result that risks triggering instability as NATO troops withdraw.
Allegations of massive fraud in Afghanistan's June election tipped the country into a political crisis, with the United Nations voicing fears that the contested outcome could revive the ethnic divisions of the 1990s civil war.
Kerry last month negotiated a deal in which poll rivals Ashraf Ghani and Abdullah Abdullah agreed to a complete an audit of the eight million votes, and for the winner to form a national unity government.
But the deal has made little progress due to further disagreements between the candidates, and no date has yet been set for the delayed presidential inauguration.
The clock is now ticking for a new president to be in office before the end of this month ahead of a NATO summit on September 4-5, when member states will decide on future finance and support for the war-torn country.
"We would like to see the inauguration ideally by the end of the month," said a US official travelling with Kerry.
"It's important for a new president to be able to go to NATO and ask for these commitments, including continued ANSF (Afghan National Security Forces) costs.
"It's in all of our interests for that to happen. That is still the goal and we are all doing everything possible to ensure that it can stay the goal.
"It'll be hard... but it's possible."
For security reasons, Kerry's visit was not announced before he landed.