Washington, Oct 20 (DPA) US officials believe Afghan President Hamid Karzai would declare his acceptance Tuesday of a presidential runoff after an investigation of voting fraud invalidated part of the August ballots, The Washington Post reported.

The Post cited unnamed senior US government officials in its report late Monday on its website that Karzai was expected to accept the runoff after what were described as tense negotiations with the president.

His former foreign minister Abdullah Abdullah would compete in the runoff as the second-placed candidate from the Aug 20 first round of voting.

Karzai had claimed outright victory in that election. Preliminary results had given him 54 percent of the votes.

However, the UN-backed Election Complaints Commission issued its investigation findings Monday, which reduced Karzai’s vote total to less than an outright majority needed to win in the first round.