US Secretary of State John Kerry is holding a second day of talks in Afghanistan to try to end a row over the result of the presidential poll.
Mr Kerry is meeting candidates Ashraf Ghani and Abdullah Abdullah, who accuse each other of electoral fraud, at the US compound in the capital, Kabul.
Mr Ghani, the winner of preliminary results in the second round, has backed an "extensive audit" of votes.
Meanwhile, 10 people have been k**ed in bomb attacks blamed on the Taliban.
Eight civilians, including several women, died when a roadside bomb blew up in southern Kandahar province. A bomb in the eastern city of Jalalabad, in Nangarhar province, claimed two more lives.
Afghanistan's current President Hamid Karzai, who came to office after the US-led overthrow of the Taliban, is stepping down after more than 10 years.
Soldier inspects blown-up car in Jalalabad (12 July 2014)
A bomb in the city of Jalalabad k**ed a civilian and a police officer on Saturday, officials said
Security concerns
US officials said they were hoping for a breakthrough on Saturday after the first day of negotiations remained inconclusive.
The US Secretary of State, who arrived in Kabul on Friday in a hastily arranged visit, earlier welcomed Mr Ghani's backing of an audit.
"No-one is declaring victory at this time. The results have yet to be finalised and so those questions have to be resolved and I'm very appreciative that Dr Ghani respects that," Mr Kerry told journalists ahead of starting the talks.
The US has been concerned at reports that Mr Abdullah, who preliminary results suggest lost the election, is planning a "parallel government".