Karzai, Rival Nearly Even in Afghan Vote

President Hamid Karzai and top challenger Abdullah Abdullah both have roughly 40 percent of the nationwide vote for president with 10 percent of polling stations counted, the Afghan election commission said Tuesday as it announced the first official returns.

If neither Karzai nor Abdullah gets more than 50 percent of the vote, the two will face each other in a runoff, likely in early October. The Independent Election Commission plans to release more results in the coming days, but final certified results of last week's election won't be ready until at least mid-September.

Low voter turnout and allegations of fraud have cast a pall over the election. Abdullah has accused Karzai of widespread vote rigging, including ballot stuffing and voter intimidation. Karzai's camp has leveled similar accusations. Both campaigns have denied the claims.

The Independent Election Commission announced that Karzai has 40.6 percent and Abdullah has 38.7 percent of the votes in the country's first official returns since millions of Afghans voted for president last Thursday.

But violence remained the backdrop to the recent election, reports CBS News correspondent Mandy Clark in Kabul. As the first returns were released today, they were overshadowed by one of Afghanistan's biggest bombings yet. A truck packed with explosives blew up in the southern city of Kandahar, killing dozens.

Deadly Car Bombs Rock Afghan City
4 U.S. Soldiers Die in Blast

The returns so far come from only 22 of the country's 34 provinces and represent votes from just 10 percent of the country's polling stations. Of the roughly 525,000 valid votes counted so far, the majority came from Kabul, nearby Parwan and Nangarhar provinces, Kunduz and Jowzjan provinces in the north and Ghor province to the west.

In the volatile south, less than 2 percent of Kandahar votes have been counted, and no votes in Helmand have been tallied, the commission said. Karzai would expect to do well in both provinces, suggesting his returns could go higher.

Both Karzai and Abdullah have claimed they were leading in early returns, but no official figures have backed those assertions.

The U.S. government urged candidates to wait for more complete results.

"We call on all parties to refrain from speculation until national results are announced," State Department spokesman Ian Kelly said.

Allegations of vote rigging mounted Tuesday.

Abdullah directly accused Karzai of fraud. A video, which could not be independently verified, is alleged to show Karzai supporters stuffing ballot boxes, Clark reports. The Karzai camp has leveled similar accusations in return.

"I don't trust what they are doing," Abdullah said. "I don't know what their announcement will be tomorrow."

Meanwhile, six presidential candidates none of them Abdullah or Karzai - warned that fraud threatens to undermine the election and could stoke violence.

Abdullah showed reporters a packet of ballots with an official stamp on the back - used to mark cast ballots - nearly all checked for Karzai. He also showed video of what he said were Karzai supporters in eastern Ghazni province marking dozens of ballots for Karzai, and a picture of a polling site in the south showing people he said were Karzai campaign officials looking over the shoulders of voters.

"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.

The election commission said it had fired four election workers in northern Balkh province for attempted fraud. Photographs showed three trying to vote with multiple cards, while the fourth was ordering voters to cast ballots for a specific candidate, said Daoud Ali Najafi, the commission's chief electoral officer.

The six presidential candidates said in a statement that dozens of complaints filed could affect the outcome of the election "to the point that many are seriously questioning the legitimacy and credibility of the results."

"Fraud in the elections could result in increased tension and violence," the six added.

The signatories are all long-shot candidates. The most prominent is Ashraf Ghani, a Western-educated former finance minister who has been suggested as a "chief executive" under the next president tasked with handling day-to-day management of the government.

Ghani earlier sent out a statement listing the complaints his campaign has submitted, including gunmen telling voters to cast ballots for Abdullah and officials stuffing ballot boxes in favor of Karzai.

The fraud claims threaten to undermine President Barack Obama's Afghanistan strategy. The Obama administration hopes the election will produce a leader with a strong mandate to confront the growing Taliban insurgency.

As of Monday evening, the independent Electoral Complaints Commission said it received more than 50 allegations of fraud that could affect the election results if true. Final results cannot be certified as legitimate until the complaints commission rules on these cases.

The final election result will not be announced for weeks. Although early results have put Karzai 2 percent ahead of Abdullah, Karzai actually needs over 50 percent to win outright. All indications show a run-off election will be needed to determine the winner - and that isn't expected until October, Clark reports.

Humayun Hamidzada, a spokesman for Karzai, said the government had the resources to respond to any violence that results from election announcements.

"Today Afghanistan has its own security institutions, today Afghanistan has a constitution and has its own rules and law," he told reporters. "If anyone tries to break the law, they will face the legal process."

CBS News' Lara Logan's coverage of Afghanistan:

For Afghans, All That Glitters is Not Gold
Marines Work and Live Hard in Afghanistan
Marines Walk Tightrope of Death
What the Afghans Really Want