KABUL - Afghan President Hamid Karzai inched closer to a first-round victory as more results came in from an election last month marred by accusations of fraud.

With results tallied from slightly less than 75 percent of polling stations, Karzai led his main challenger Abdullah Abdullah by 48.6 percent to 31.7 percent. Karzai needs more than 50 percent to avoid a second in a run-off.

The fresh results will do little to end more than two weeks of uneasy suspense over the outcome. Abdullah's camp says the authorities stuffed ballots for Karzai on a huge scale.

Western leaders initially hailed the August 20 election because Taliban fighters failed to scupper it with attacks and threats against voters. But as reports of fraud have mounted, those assessments have grown more circumspect.

The election is key element in Western plans to bring stability to Afghanistan and to prevent militants from using it as a haven.

More than 100,000 foreign troops in a U.S.-led coalition are deployed in the country fighting the Taliban, who were ousted from power in 2001 but are now resurgent.

U.S. and U.N. officials say they are waiting for the final tally and the outcome of fraud investigations before concluding whether the result is fair.

The votes yet to be counted are mainly from the south and southeast, heartland of Karzai's support, where returns so far show the president with a substantial lead that could be big enough to put him over the 50 percent overall.

Those are also the parts of the country where Abdullah says fraud was most widespread, suggesting decisions in coming weeks on whether to exclude ballots could decide the outcome.

The election commission said it had so far annulled the results from about two percent of polling stations after investigating indications of fraud.

A separate body, the Electoral Complaints Commission, mainly appointed by the United Nations, can also annul results. It is investigating more than 2,000 complaints, including more than 600 it says are serious enough to affect the outcome.

Abdullah says he will reject any result if fraud played a role. On Saturday, his staff handed out lists of hundreds of polling stations where they said the official results looked dubious, including many where Karzai won all votes cast, often with round numbers.

In one of several examples that appear in tables on the election commission's Web site, Karzai won every single vote cast in Torzai village in southern Kandahar province, including exactly 500 votes each at four of eight polling stations there.

A run-off, if needed, is tentatively scheduled for October 1, but Western diplomats expect that date to slip because of delays in counting the votes so far.

(Writing by Peter Graff, editing by Angus MacSwan)