Abdullah Abdullah, once Karzai’s foreign minister, said Saturday he was in contact with other campaigns to explore the possibility of a coalition candidacy in case none of the 36 candidates won enough votes in last Thursday’s ballot to avoid a runoff, probably in October.

The accusations, which Karzai’s spokesman denied, are the most direct Abdullah has made against the incumbent in a contest that likely has weeks to go before a winner is proclaimed. Both Abdullah and Karzai claim they are in the lead based on reports from campaign pollwatchers monitoring the count.

Officials of Abdullah’s campaign have alleged fraud in several southern provinces where the insurgency is strongest and Karzai had been expected to run strong.