The opposition challenger to Afghan President Hamid Karzai says he will not participate in the November 7 run-off election.
In an emotional speech in Kabul Sunday, Abdullah Abdullah accused the government of failing to create the conditions for a fair vote.
Still, the former foreign minister did not urge Afghans to boycott the run-off, which was triggered when a U.N.-backed investigation found that the initial vote in August had been marred by massive fraud.
Election officials say the run-off will still take place with Mr. Karzai as the only candidate.
The president's campaign spokesman, Waheed Omar says the election is the right of the Afghan people.
British Prime Minister Gordon Brown says he spoke to the Afghan leader Sunday, and that Mr. Karzai said he wants to issue a "unity manifesto" for the Afghan people.
Mr. Brown told reporters he believes Mr. Abdullah withdrew from the race "in the interests of national unity."
The British prime minister said the next Afghan government must make fighting corruption a top priority.
He said his top concern is the safety of British troops in Afghanistan.
The British military said Sunday one of its soldiers was killed in an explosion in southern Helmand province on Saturday.