KABUL - President Hamid Karzai's campaign and chief rival Abdullah Abdullah both said on Friday they had won Afghanistan's election, but Washington's chief envoy warned candidates not to declare victory prematurely.

Both camps said unofficial counts by campaign workers showed they had won enough votes to avoid a potentially destabilizing second round of voting in October. Election officials said no confirmed results had been released.

Initial results show that the president has got a majority, Karzai's campaign manager Deen Mohammad told Reuters. We will not get to a second round.

Abdullah, Karzai's former foreign minister, dismissed the Karzai camp's victory claim and said he was on track to win in the first round after Thursday's vote, which went ahead despite sporadic Taliban violence.

I'm ahead. Initial results from the provinces show that I have more than 50 percent of the vote, Abdullah told Reuters.

Official preliminary results are not due for two weeks, but counting began immediately after polls closed on Thursday and is largely complete.

Analysts have warned that uncertainty over the outcome or accusations of widespread fraud could lead to civil unrest. U.S. envoy Richard Holbrooke said he was certain the outcome of the vote would be disputed.

We always knew it would be a disputed election. I would not be surprised if you see candidates claiming victory and fraud in the next few days, Holbrooke said at a briefing in Kabul with election observers.

Holbrooke said Washington had an agnostic position and did not support any early, unofficial victory declarations.

A U.S. embassy spokeswoman said only the Independent Election Commission (IEC) was in a position to announce results and anything else was just speculation.

Polls conducted before the election showed Karzai in the lead but suggested he would not win more than 50 percent of the vote needed to avoid a run-off.

Afghan and U.S. officials have breathed a sigh of relief after the relatively peaceful election, which had been marked by a dramatic escalation in violence in the weeks leading up to the vote.

Afghan and international forces suspended offensive operations on voting day, but attacks continued nonetheless.

Three U.S. troops were killed in roadside bomb and mortar attacks in the east and two British soldiers were killed in an explosion in southern Helmand on Thursday, the military said.

PATIENCE URGED

The 6,200 polling stations are required to make their results available to the public as they tabulate them to prevent fraud.
Zekria Barakzai, deputy head of the IEC, urged patience.

We cannot confirm any claims by campaigning managers. It's the job of the election commission to declare the results. They should be patient, Barakzai said.

An independent Afghan monitoring body, FEFA, said it was concerned about the quality of the poll after receiving reports from its observers across the country of fraud and interference.

The International Republican Institute, a U.S.-based group that monitors elections, said Thursday's vote was marked by serious problems, but had so far been credible.

Barakzai said two convoys of election workers transporting ballot boxes had been attacked following the vote. In one case, in Balkh province in the north, an election worker was killed and ballots that had already been counted were burned.

He said preliminary figures showed overall turnout was around 40-50 percent, roughly in line with estimates by Western diplomats before the poll. About 70 percent of registered voters cast ballots in the 2004 presidential poll.

Much is likely to depend on turnout in southern areas, such as Karzai's home province of Kandahar, where the president draws his strongest support but where voters faced the brunt of Taliban attacks and intimidation.

Abdullah's spokesman, Fazl Sangcharaki, said the north had voted solidly for Abdullah, except in Jowzjan province, home of Uzbek militia chieftain Abdul Rashid Dostum, who returned to the country days before the vote to campaign for Karzai.

Western backers have expressed concern about Karzai's tactic of seeking support from former militia chiefs, afraid that deals made to secure votes could bring warlords back to power.

In Washington, President Barack Obama hailed the conduct of the election and vowed to press on with his strategy, which has involved sending thousands of additional troops to the country.

The election was a test for Obama's new strategy aimed at reversing Taliban gains. U.S. combat casualties have risen amid a U.S. troop buildup and opinion polls have shown weakening American backing for the war.

(Writing by Paul Tait; Editing by David Fox)