KABUL (CNN) -

An audit of Afghanistan's disputed presidential election results will begin within a day in Kabul, and the two candidates will accept its determination of who won, U.S. Secretary of State John Kerry said Saturday.

"Make no mistake. These will be the first steps of what will obviously be a hard, difficult process and we will be working hand in hand with both candidates," Kerry said. "In keeping with each of the candidate's request, this audit will be conducted with the highest international standards."

The inauguration of the new president, originally scheduled for the first week of August, will be postponed while the audit of votes cast for Abdullah Abdullah and Ashraf Ghani is conducted, Kerry said. Both candidates stood beside him.

Kerry announced the brokered deal amid fears the country could descend into chaotic bloodshed. He extended his stay here to deal with the issue.

Abdullah cited how "there were previous challenges in relation to the election, and today we are happy to announce" the agreement for an audit.

Ghani said he was "delighted" by the accord in which "the candidates will abide by the will of the people."

The two candidates clasped hands and raised them for the cameras before leaving.

Ballots cast in the provinces will be brought to Kabul by NATO-led International Security Assistance Force and Afghan national security forces for the audit, Kerry said.

Kerry arrived in Kabul on Thursday for the unannounced visit amid concern over signs of growing division following the country's contested presidential runoff election.

Despite efforts by the Taliban to disrupt the election, about 8 million votes were cast in June 14 balloting and provisional results showed Ghani ahead with roughly 56% support to 43% for Abdullah, according to Afghanistan's Independent Elections Commission.

Both candidates have alleged large-scale vote fraud and manipulation during the runoff last month.

The audit will take weeks to complete, Kerry said.

Roadside bombing

Amid continued insecurity, a civilian vehicle hit a roadside bomb in the Panjwai district of southern Kandahar province on Saturday, killing eight members of one family, including four women, according to the Afghan Interior Ministry. Two children were injured.

Only two days earlier, six members of a mine-removal team were killed and three others were abducted in an ambush by gunmen in western Herat province, a local police official said.

The United States is withdrawing most of its troops by year's end, reducing the primary leverage it has had in Afghanistan. But it still supports the country with billions of dollars in foreign aid.

The international community, which fears a resurgence of the Taliban, is keen to see Afghanistan continue on the path to democracy.

'Critical moment'

The Obama administration says it has no favored candidate but wants to see a credible and transparent process that produces a president who can bring Afghanistan together and govern effectively.

Senior administration officials said Friday that Kerry's meeting with the two candidates had focused on the need to preserve the gains Afghanistan has made over the past 13 years, through a legitimate political transition.