Kerry in Kabul to seek resolution on election dispute

US Secretary of State John Kerry will hold talks in Kabul today aimed at pressuring Afghanistan's rival presidential candidates to resolve disputed elections and have the winner installed by the end of this month.

Allegations of massive fraud in Afghanistan's June vote 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 visited Kabul only last month to negotiate a deal in which poll rivals Ashraf Ghani and Abdullah Abdullah agreed to an audit of all eight million ballots, and for the winner to form a national unity government.

But the deal soon faltered due to further disagreements between the candidates, and no date has yet been set for the delayed presidential inauguration -- an impasse that risks worsening instability as NATO troops withdraw.

Kerry is due to meet the US ambassador today followed by an audience with outgoing Afghan president Hamid Karzai. A press conference is expected later in the afternoon.

The latest visit comes as Washington responds to another legacy of its foreign policy in the Muslim world, with US President Barack Obama overnight authorising airstrikes on Islamist extremists in Iraq.

Obama said the strikes were necessary to prevent a "genocide" by Islamic State militants who have targeted Iraq's minorities since seizing vast swathes of the country's northern and western regions.

The clock is now ticking for a new Afghan 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.

According to preliminary election results, former World Bank economist Ghani easily won the run-off election.

But Abdullah, a former anti-Taliban resistance fighter, alleged massive ballot-box stuffing and refused to accept the result, with his supporters urging him to set up a "parallel government".