By ALISSA J. RUBIN and CARLOTTA GALL

Published: September 24, 2010

KABUL, Afghanistan — Evidence is mounting that fraud in last weekend’s parliamentary election was so widespread that it could affect the results in a third of provinces, calling into question the credibility of a vote that was an important test of the American and Afghan effort to build a stable and legitimate government.

The complaints to provincial election commissions have so far included video clips showing ballot stuffing; the strong-arming of election officials by candidates’ agents; and even the handcuffing and detention of election workers.

In some places, election officials themselves are alleged to have carried out the fraud; in others, government employees did, witnesses said. One video showed election officials and a candidate’s representatives haggling over the price of votes.

Many of the complaints have come from candidates and election officials, but were supported by Afghan and international election observers and diplomats. The fraud appeared to cut both for and against the government of President Hamid Karzai, much of it benefiting sometimes unsavory local power brokers.

But in the important southern province of Kandahar, where election officials threw out 76 percent of the ballots in last year’s badly tainted presidential election, candidates accused the president’s influential half brother, Ahmed Wali Karzai, of drawing up a list of winners even before the Sept. 18 election for Parliament was carried out.

“From an overall democracy-building perspective it does not look rosy,” said one diplomat who asked not to be identified because he was not authorized to speak to the news media.

The widespread tampering and bare-knuckle tactics of some candidates raised serious questions about the effort to build a credible government that can draw the support of Afghans and the Obama administration and its NATO partners as they re-evaluate their commitment to the war.

American and international diplomats kept their distance from the tide of candidate complaints this week, and NATO and American Embassy officials said little other than that the election was an Afghan process and that it was the Afghans who were responsible for its outcome.

But a less than credible parliamentary election, following last year’s tarnished presidential vote, would place international forces in the increasingly awkward position of defending a government of waning legitimacy, and diplomats acknowledged that it could undermine efforts to persuade countries to maintain their financing and troop levels.

The Election Complaints Commission said Thursday that it had received more than 3,000 complaints since last Saturday’s election. So far they have registered case files on nearly 1,800 of those complaints — 58 percent of which were considered serious enough to affect the outcome of the balloting. That may change in the course of investigations but that preliminary figure is high, election monitors said.

The complaints are not evenly distributed and were markedly worse in 13 of Afghanistan’s 34 provinces. In those 13, at least half the complaints were deemed to be high priority — forecasting bitter fights over the outcome.

In addition, complaints in four provinces — Kandahar, Nuristan, Zabul and Paktika — have yet to be categorized, but fraud is expected to be extensive and has already been widely reported.

“That preliminary figure is bad,” said a knowledgeable international observer.

Many analysts predicted there would be serious fraud in the unstable Pashtun belt, in the south of the country, an important base for both the Taliban insurgents and President Karzai. But serious complaints were also coming from provinces in the north and west.

Interviews by The New York Times in 10 provinces and discussions with election monitors elsewhere found a resurgence of local strongmen with armed backers who coerced and threatened voters, and the involvement of local government employees in ballot stuffing.

“In general the election has been a free-for-all, in that different power blocs were putting forward their candidates in different places,” said an international official who has been following the elections.

“It’s not necessarily the pro-Karzai bloc that has done so well, it’s that the Parliament will be more dependent on big power brokers,” the official said, adding that they would be more likely to make deals with Mr. Karzai that did not necessarily serve the Afghan people.

Lawmakers and opposition candidates openly accused the Karzais, and in particular Ahmed Wali Karzai, the most powerful official in Kandahar, of fixing the election for a list of favored candidates.

“Of the list of 50, it is already decided who will come” to Parliament, said Izzatullah Wasefi, an opposition candidate from Kandahar.

Nur ul-Haq Uloomi, a member of Parliament who won the largest vote from Kandahar in 2005, and has since become an outspoken critic of the corruption and inefficiency of the Karzai government, accused Ahmed Wali Karzai of manipulating the vote to deny him another term.

He said he had sent one of his campaign managers to the chairman of the Independent Election Commission, Fazal Ahmad Manawi, in Kabul to warn of potential fraud before the election, but he was rebuffed.