KABUL (AFP) – US Secretary of State John Kerry sought Friday to mediate an end to the political crisis in Afghanistan, warning that a bitter dispute over presidential polls threatened the country’s future.

As the top US diplomat met separately with the rival candidates, Ashraf Ghani and Abdullah Abdullah, Kerry stressed that results released Monday showing Ghani in the lead were “preliminary”.

“They are neither authoritative nor final, and no-one should be stating a victory at this point in time,” Kerry said, as he held back-to-back meetings in the heavily-fortified US embassy.

“We want a unified, stable, democratic Afghanistan. It is important that whoever is president is recognised by the people as having become president through a legitimate process,” he said.

The next government should be one that “can unify” the people and “lead in the future,” Kerry said.

Despite Monday’s announcement, Abdullah, who has already once lost a presidential bid in controversial circumstances, has declared himself the true winner, saying massive fraud robbed him of victory in the June 14 run-off vote.

In a swift boost for Kerry’s diplomacy, Ghani threw his backing behind US calls for a wide audit of the elections.

“Our commitment is to ensure that the election process enjoys the integrity and the legitimacy of the people of Afghanistan and the world,” Ghani told reporters as he met with Kerry.

“Therefore we believe in the most intensive and extensive audit possible to restore faith.”

– High stakes –

A statement from the office of outgoing President Hamid Karzai said UN officials had put forward a plan late Thursday to audit some 8,000 ballot boxes, representing 43 percent of the total votes — or around 3.5 million votes.

Ghani said he and his supporters were committed to “an inclusive government. A government that could represent all of Afghans, and serve every Afghan citizen in the manner that every Afghan deserves according to the constitution”.

The stakes could not be higher, as the next president will have to steer the war-torn country as international troops withdraw, leaving Afghan forces to fight a bloody, stubbornly resilient Taliban insurgency.

Abdullah thanked Kerry for coming as well as continued US support and for “the sacrifices that your people have done alongside the Afghans”.

But he said that “the future of our achievement depends upon the success of the democratic process”.

“It’s not the number of troops, it’s not the money,” Abdullah said, adding that the US once again had “proved your commitment to helping Afghanistan, in saving Afghanistan, and in saving the democratic process here”.

The election stand-off has sparked fears that protests could spiral into ethnic violence — and even lead to a return of the fighting between warlords that ravaged Afghanistan during the 1992-1996 civil war.

– Need for thorough audit –

“Our hopes are that there is a road that can be found that will provide that capacity for the questions to be answered, for people’s doubts to be satisfied and hopefully for a future to be defined,” Kerry said.

But he warned that was not “an automatic at this point”.

The United States was “going to push for the very best, most credible, most transparent and most broadly accepted outcome that we can under the circumstances,” a senior US official said earlier.

Auditors may look at districts with a very high turnout, or a perfectly round number of recorded votes, or where the number of women voters outnumbered men, “which in the Afghan context seems like an unlikely outcome”.

UN officials have said a full audit of the results could take up to two weeks, but some Afghan officials are pressing to stick by an election calendar that would see the new president inaugurated on August 2.

After more than 13 years of war following the 2001 US invasion to oust the hardline Taliban regime, President Barack Obama has said all American forces will be withdrawn by the end of 2016.

The 30,000 US troops on the ground will be whittled down to 9,800 next year.

The Obama administration is also desperately waiting for Afghan leaders to sign a bilateral pact governing the presence of US forces in the country beyond this year.

Karzai walked away from the deal, but both presidential candidates have said that they would sign it.