**The UN has called for a crackdown on Afghan poll fraud, amid mounting concerns about irregularities from last month’s presidential election.**UN envoy Kai Eide said results from all ballot boxes in areas where there is any evidence of fraud must be annulled.
The BBC has learned that the US ambassador in Kabul and a senior UN official met President Hamid Karzai on Monday night to discuss their concerns.
Mr Karzai was close to outright victory in the latest partial results.
The 20 August vote has been overshadowed by claims of mass electoral fraud.
The BBC’s Chris Morris in Kabul says more results are due to be declared on Tuesday and there are concerns about their legitimacy.
Afghan election officials at the weekend annulled results from 447 poll centres, but there are fears the fraud was much more widespread, says our correspondent.
The latest poll results on Sunday showed Mr Karzai near to the 50% threshold needed to avoid a run-off ballot, with three-quarter of votes counted.