Those talks among Afghans on both sides of the conflict were supposed to be the next crucial step in a U.S.-Taliban peace deal, signed less than two weeks ago. But the dispute between the top two candidates in last year's presidential election over who actually won means the Afghan government side appears unable to present a united front.

Washington's peace envoy Zalmay Khalilzad was reportedly going back and forth between the two Afghan rivals into the early hours Monday, with some local media reports saying he made five separate visits. His shuttle diplomacy apparently won him a few hours to continue his mission to try to break the stalemate.

When Washington and the Taliban insurgents signed the deal, the promise was that Afghans would sit down and negotiate a road map for their country's future. They are looking to hammer out such thorny issues as women's rights, free speech and the fate of tens of thousands of armed men on both sides of the 18-year war. Those negotiations were set to be held Tuesday in Oslo.

The U.S. has said its troop withdrawal from Afghanistan will be linked to the Taliban keeping their counter-terrorism promises, but not to the success of talks between the Taliban and the Afghan government.

Afghanistan's election commission has declared incumbent President Ashraf Ghani as the winner of September's vote. His former partner in a unity government, chief executive Abdullah Abdullah, as well as the election complaints commission say the results are fraught with irregularities. As a result, both Ghani and Abdullah have declared themselves winners.

The two candidates are also backed by warlords who have a stake in who becomes president, complicating negotiations to break the stalemate being conducted Khalilzad.

The rival presidential candidates called journalists to their respective inaugurations early Monday, only to delay them for a few hours while more talks were being held.

A senior member of Abdullah's team, Basir Salangi, told local Afghan channel Tolo TV that the U.S. peace envoy has asked both sides to delay their inaugurations for three days to sort out the stalemate. Abdullah reportedly said he was ready, but would go ahead with his ceremony Monday if Ghani refused to postpone.

Taliban spokesman Zabihullah Mujahed, in response to questions from The Associated Press, said late Sunday that the Taliban were still committed to the deal, but said the dueling presidential inaugurations "are not good for the Afghan nation."

As well as competing candidates, Khalilzad still has to get some agreement on a prisoner release, which was supposed to be settled before the intra-Afghan negotiations could begin. The peace deal signed by the U.S. and Taliban said 5,000 Taliban prisoners and up to 1,000 captives from the government side would be freed as a goodwill gesture ahead of the intra-Afghan negotiations.

Ghani had previously said he won't release the Taliban prisoners, even as U.S. Secretary of State Mike Pompeo called on all sides to stop posturing and free their prisoners, some of whom have already served their sentences. Pompeo called on all sides get on with talks about the country's future.

The Taliban spokesman told AP that the group wants their prisoners released and were ready to free the captives they're holding. Mujahed said they did not want to see a delay, but reiterated that if it occurred "we remain committed to the agreement."

In a tweet, Afghanistan's former deputy foreign minister, Jawed Luddin, thanked Washington for trying to sort out Afghanistan's political turmoil while calling the squabbling "a mess."

"Thank you USA for trying to sort out our political crisis - yet again. We know you must be sick of it - as are we Afghans," Luddin said.

"You and us both had a hand in bringing about the mess that is today's Afghan politics. But I wish we Afghans felt half as responsible for the mess as you do," he added.

The deal signed by the U.S. would allow Washington to end its involvement in Afghanistan and bring home U.S. troops over a period of 18 months.