Media playback is unsupported on your device Media caption Abdullah Abdullah: "Lots of fraudulent ballot papers were included without being validated"

An audit of votes from Afghanistan's disputed presidential election has restarted without observers from the camps of either candidate.

Candidate Abdullah Abdullah had withdrawn his observers after raising concerns over fraud.

The team sent by his rival, Ashraf Ghani, said it pulled out after having been asked to do so by the UN.

Both Mr Abdullah and Mr Ghani have claimed victory in June's poll and both have alleged widespread fraud.

The two candidates have agreed to form a government of national unity but have so far failed to reach a deal.

Auditing all eight million votes cast in the June run-off began a month ago and could take weeks to complete.

The UN said Mr Abdullah's decision to withdraw from the process was "regrettable".

How rival candidates compare Ashraf Ghani Abdullah Abdullah Technocrat and former World Bank official. Open to talks with Taliban Former anti-Soviet resistance member. Wary of Taliban talks Leading in Pashtun-dominated southern provinces Ahead in mainly Tajik northern areas Backed by Rashid Dostum, an Uzbek ex-warlord accused of human rights abuses Supported by wealthy Balkh governor Atta Mohammad, a bitter Dostum rival Has support of Qayyum Karzai, brother of President Karzai Also has backing of Mohamed Mohaqiq, powerful leader of ethnic Hazaras Ahmed Zia Masood, whose brother was a famous resistance hero, helped balance ticket Gul Agha Sherzai, an influential Pashtun, helped bring ethnic balance to ticket

Analysis: Dawood Azami, BBC World Service

Despite all the reports from Kabul of impending doom and collapse, there are still genuine reasons to be optimistic while we wait for a new president to be announced.

The two candidates agree on at least two major points. Both have committed themselves to signing a security agreement with the US which will allow foreign forces to stay in Afghanistan after 2014. And both have signed a document pledging to form a national unity government which will accommodate whichever side loses.

But the main contentious issue is how to distribute power and positions.

Abdullah Abdullah's team seem to be trying to extract maximum concessions for whoever loses. Disputed preliminary results suggested they were heading for defeat. They want devolution of power and more portfolios for the losing side and insist the position of "chief executive" - that both sides have agreed to establish by presidential decree - should have more powers.

Mr Ghani's camp seems reluctant to dilute the president's powers and give too much away.

The wrangling at the top has hit the economy and is being exploited by the Taliban who have staged some of their biggest attacks since being ousted in 2001. The public just want a quick end to the crisis.

Image copyright Mahfouz Zubaide/BBC Image caption The audit could take weeks to complete

Mr Abdullah was the frontrunner in the first round in April but did not secure an outright majority.

Preliminary results after a second round in June put Mr Ghani ahead.

Mr Abdullah's team alleges hundreds of thousands of ballots are fraudulent and should be thrown out.

Some of his supporters have threatened to stage major street protests, and the BBC's David Loyn in Kabul says it feels a very dangerous moment in Afghanistan.

The Abdullah team said they would boycott the audit when it moved into its final stage this week, and only a few ballot boxes were thrown out.

A member of Mr Ghani's team said the Abdullah camp "know they have lost the election and... are trying to make excuses".