Afghanistan’s troubled presidential election plunged deeper into crisis yesterday when one of the main contenders accused a deputy of President Hamid Karzai of orchestrating fraud in favour ofhis rival.

Supporters of Abdullah Abdullah, a former foreign minister, released an audio recording they said was Vice President Mohammad Karim Khalili encouraging vote-rigging in favour of Ashraf Ghani, the other contender in the race.

Khalili’s and Ghani’s staff dismissed the recording as a fake.

Allegations of mass fraud have shadowed the outcome of the vote, which was meant to be the first democratic transition of power in Afghanistan’s history ahead of the withdrawal of international combat troops at the end of this year.

The eight million votes cast in the second round of the election, held in June, are currently being audited under UN supervision, according to a deal brokered by the United States.

The audit has also been dogged by delays as Abdullah and Ghani have not been able to agree on some technicalities, such as how to disqualify votes.