KABUL — International pressure was mounting Saturday on Afghanistan's president to respect imminent findings from a fraud investigation that seem likely to force him into a runoff.

At the same time, envoys were urging both candidates to strike a deal to end the country's election crisis rather than actually going forward with a potentially divisive and costly second vote.

The Aug. 20 poll was marred by charges of ballot-stuffing and voter coercion, mostly to Karzai's benefit. The fraud decisions — set to be announced as early as Saturday — could force a runoff between him and top challenger Abdullah Abdullah.

Both candidates deny they are negotiating to avert a second round. Karzai's camp is adamant he has won the first round outright, while Abdullah says a runoff is assured.

U.N. Secretary-General Ban Ki-moon, U.S. Secretary of State Hillary Rodham Clinton and British Prime Minister Gordon Brown called the candidates Friday as concerns grew over who will lead the country, and when.

The talks are focused on getting Karzai to accept rulings showing a probable second round, an international official familiar with the discussions said.

The political crisis, and rising U.S. casualties in the war against insurgents, have prompted the Obama administ5ration to review its entire Afghanistan war strategy. Three American troops died in bomb attacks in the south and east, the latest casualties reported by NATO forces Saturday.

The French Foreign Ministry called on all parties to respect results of the fraud investigation and work toward either Karzai's inauguration or preparations for a runoff.

French Foreign Minister Bernard Kouchner, U.S. Democratic Sen. John Kerry and former U.S. ambassador to Afghanistan, Zalmay Khalilzad, were in Kabul on Saturday.

Kerry's trip was planned before the electoral crisis, but he has met with both candidates "to speak for Washington about the need for a legitimate outcome," according to a U.S. Embassy official.