President Hamid Karzai and top challenger Abdullah Abdullah both have roughly 40 percent of the nationwide vote for president with 10 percent of ballots counted, the country's election commission said Tuesday.

The commission said Karzai has 40.6 percent and Abdullah has 38.7 percent in the country's first official returns since the nation voted for president last Thursday.

The early returns are based on only 10 percent of the country's ballots. The commission plans to release partial results each day the next several days. Final, certified results won't be made public until mid or late September.

The commission said it had based the count on 524,000 valid votes after throwing out about 31,000. Less than 2 percent of Kandahar votes have been counted, and no votes in Helmand have been counted, the commission said. Karzai would expect to do well in both provinces, suggesting his returns could go higher.

If neither Karzai or Abdullah gets more than 50 percent of the votes, the two will face each other again in a run-off.

Karzai supporters have already said that the president won close to 70 percent of the vote, but Abdullah has alleged that massive fraud has been carried out in favor of the president.

"If the widespread rigging is ignored this is the type of regime that will be imposed upon Afghanistan for the next five years, and with that sort of a system, a system that has destroyed every institution, broken every law," Abdullah said at a news conference just before the results were announced.

Six Afghan presidential candidates, including one being floated as a potential "chief executive" for the next government, warned Tuesday that fraud allegations threaten to undermine the recent election and could stoke violence.

Low voter turnout and allegations of fraud have cast a pall over the election. In particular, some worry that supporters of Abdullah could vent fury if he comes in second with no chance at a runoff.