Secretary of State John Kerry, center, was dispatched to Kabul to forestall possible violence resulting from the electoral dispute between Afghan presidential candidates Ashraf Ghani, right, and Abdullah Abdullah. (Jim Bourg/AFP/Getty Images)

– Just days after Secretary of State John F. Kerry brokered an end to Afghanistan’s election crisis, the deal has run into trouble because of disagreements among the two rival presidential candidates.

The agreement was intended to resolve a weeks-long impasse that had threatened to split the country. But implementation of the deal has been held up by confusion over whether Afghan or international institutions will lead the inspection of the 8.1 million votes cast in a June 14 runoff that was marred by fraud.

The electoral dispute has raised alarm that conditions could deteriorate further in a country already battling a resilient insurgency. Highlighting the country’s fragility, a suicide bomber driving a truck packed with explosives killed at least 45 people in a crowded market in the southeastern province of Paktika on Tuesday, a spokesman for the provincial governor said. The Afghan Defense Ministry said 89 people had been killed. The conflicting death toll reports could not immediately be reconciled.

The White House had dispatched Kerry to Kabul last week to forestall possible violence after candidate Abdullah Abdullah’s threats to declare his own government. An ambitious deal to recount the votes and form a national unity government was clinched in marathon talks that ended Saturday.

But on Monday, the audit of the ballots, meant to begin within 24 hours of the announcement of the accord, was postponed indefinitely to addresstechnical disputes, Afghanistan’s Independent Election Commission (IEC) said. Western officials, who spoke on the condition of anonymity because of the sensitivity of the issue, said they expected the vote counting to begin Wednesday or Thursday.

The campaign of former foreign minister Abdullah — who last month accused the IEC of helping rig the vote — said it was promised that international bodies would take charge of the audit.

The team of the opposing candidate — former World Bank official Ashraf Ghani — says no such stipulation was included in the deal. According to Afghan law, the IEC is required to carry out the audit. The United Nations can play only a supervisory role, Ghani’s campaign says.

“There was an agreement in the discussions that there would be an international audit, not an Afghan-led audit,” said Mohammad Mohaqiq, one of Abdullah’s two vice-presidential candidates and a former warlord who commands strong support among Afghanistan’s ethnic Hazara community. “If the IEC is in charge of this audit, then all of these efforts will translate into nothing — a zero.”

It was not clear Tuesday why the two sides had such differing accounts of what the agreement involved.

But a senior U.S. official said Monday that although the IEC “technically conducts the audit, it’s being done under the auspices of and the supervision by the U.N.”

“Obviously something of this complexity is still being worked out,” said the official, who asked not to be identified because of the sensitivity of the issue. “There will be many, many moving parts of this over a period of at least another month.”

On Tuesday, a senior State Department official said that “all parties continue to meet together” to discuss the process. “We’ve seen nothing to indicate that there’s any walk-back from commitment” to the deal, the official said, also speaking on the condition of anonymity.

But that such a high level of uncertainty over the process has cropped up so soon after negotiations underscores the polarized nature of Afghanistan’s political landscape.

The first round of elections was held April 5. Abdullah won the most votes but fell short of the majority needed to take the presidency. In the second round, elections officials said, Ghani secured 56 percent of the votes, according to a preliminary count. But authorities acknowledged that the results were tarnished by vote tampering.

The new president’s inauguration was initially scheduled for Aug. 2. But the United Nations requested that President Hamid Karzai postpone the date to allow for the audit and negotiations over a national unity government to take place.

Should the rift over the audit process remain unresolved, it could endanger one of the central goals of the accord: the formation of a consensus government that would eventually choose a prime minister, transitioning Afghanistan from a presidential to a parliamentary system of government.

Right now, Karzai possesses extensive powers. The new political framework would immediately create a chief executive post subordinate to the president, Mohaqiq said. The chief executive position would be a prototype for the prime minister job. The hope is that a parliamentary system would ease ethnically based grievances by enshrining a more even distribution of power, U.S. officials said.

There was no claim of responsibility for the bombing in Paktika. But Afghan forces are struggling against a Taliban-led insurgency that has killed a growing number of the country’s soldiers and civilians. According to a U.N. report released last week, civilian casualties here rose by 24 percent during the first half of the year.

Foreign troops under the command of the International Security Assistance Force are scheduled to withdraw by the end of 2014, a rapidly approaching deadline that has Afghans and international observers worried that the country could face increasing Taliban advances or the kind of ethnic bloodshed that tore Afghanistan apart in the 1990s.

Abdullah, of mixed Tajik and Pashtun heritage, enjoys the backing of the country’s Tajik community in the north and west. Ghani, an ethnic Pashtun, is popular among Pashtun populations in the east and south.

The United States is eager to leave behind a more stable Afghanistan, having invested hundreds of billions of dollars since 2001, when U.S. troops invaded to topple the Taliban government.