Kabul ? Afghanistan’s political opposition accused President Hamid Karzai on Sunday of delaying release of a U.N.-backed investigation into fraud in the August presidential balloting and pressuring election officials to declare him the winner.

International demands mounted for Karzai to agree to a runoff if the fraud probe shows that he failed to win a majority of votes in the Aug. 20 ballot.

Preliminary results showed Karzai won the election with more than 54 percent of the vote. However, if the Electoral Complaints Commission voids enough Karzai votes, the incumbent would be forced into a runoff against his chief challenger, Abdullah Abdullah.

The complaints panel finished its investigation last week. But the announcement of its findings has been repeatedly delayed because the separate, Karzai-influenced Independent Election Commission has questioned the panel’s methodology and statistical formulas.

Abdullah’s deputy campaign manager, Saleh Mohammad Registani, accused Karzai of pressuring his supporters on the election commission to delay release of the fraud probe because they will show him below the 50 percent threshold to avoid a second round of voting.

“Karzai is the main problem in this situation,” Registani told The Associated Press. He said Karzai was insisting that the commission announce that he had won a clear majority — even after the fraud probe.