Afghanistan's troubled presidential election plunged deeper into crisis when one of the main contenders accused a deputy of President Hamid Karzai of orchestrating fraud in favour of his rival.
Supporters of Abdullah Abdullah, a former foreign minister, released an audio recording they was of Vice President Mohammad Karim Khalili encouraging vote-rigging in favour of Ashraf Ghani, the other contender in the race.
Mr Khalili's and Mr Ghani's staff dismissed the recording as a fake.
Allegations of mass fraud have overshadowed the outcome of the vote.
It was was meant to be the first democratic transition of power in Afghanistan's history.
It comes before the withdrawal of international combat troops at the end of this year.
The 8m 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 Mr Abdullah and Mr Ghani have not been able to agree on some technicalities, such as how to disqualify votes.
The recording released today is the most recent that Mr Abdullah's campaign alleges.
It is evidence of high-level collusion in an effort to ensure Mr Ghani, a former finance minister and World Bank technocrat, is declared the winner.
The speaker allegedly encourages cheating at the highest level of the administration to help Mr Ghani win.