Afghan presidential candidate Ashraf Ghani ruled out a coalition government with his rival Abdullah Abdullah yesterday, quashing hopes for a power-sharing deal to defuse tensions that have threatened to split Afghanistan along ethnic lines.

Ghani and Abdullah have locked horns since the June 14 second-round run-off, accusing each other of trying to manipulate the vote and declaring victory in the contest to succeed Hamid Karzai as president.

Prompting speculation a back-room power-sharing deal was in the making, officials have delayed the announcement of preliminary election results until tomorrow, potentially giving both candidates more time to find ways to end the impasse. But speaking to reporters yesterday, Ghani explicitly denied he sought a coalition government.

"People are concerned and the question they have been asking is if we have made any deal. Our answer is clear: we have not made any deal," Ghani said

The protracted dispute over the election has all but destroyed Western hopes for a smooth transition of power in Afghanistan, where the atmosphere is already nervous as most US-led troops prepare to pull out this year.

Abdullah, a former anti-Taliban resistance fighter, draws his support from the Tajik minority in northern Afghanistan while Ghani, a former World Bank economist, represents the Pashtun majority.

As their standoff intensified, Afghanistan has become awash with speculation about a broader rift along ethnic lines or more violence unless they agree to accept the outcome of the vote or agree on a compromise of power-sharing.

Adding another layer of complexity to an already-tense situation, Taliban insurgents have vowed to disrupt the election process. Yesterday, militants set fire to 200 oil tanker trucks supplying fuel for Nato forces near Kabul.

Ghani's aides, citing election observers, say he is in the lead in the run-off by at least one million votes.

Abdullah, for his part, has accused Karzai, an ethnic Pashtun, of playing a role in the alleged rigging in Ghani's favour, and last week thousands of Abdullah's supporters marched in a peaceful protest on the presidential palace.

In response to allegations of mass fraud, the Independent Election Commission is now recounting votes from 1930 polling stations across the country and will announce its findings tomorrow.