London, Aug 28 - US special envoy to Afghanistan Richard Holbrooke had an 'explosive' meeting with Afghan President Hamid Karzai over the country's election, according to the BBC.

Holbrooke raised concerns about ballot-stuffing and fraud by a number of candidates' teams, the BBC quoted unnamed sources as saying.

The US envoy also said a second-round run-off could make the election process more credible, making the suggestion twice in the course of the meeting.

The meeting, held Aug 21 - a day after the election, was described as 'explosive' and 'a dramatic bust-up'.

Karzai reportedly reacted very angrily and the meeting ended shortly afterwards, the sources said.

However, a spokeswoman for the US embassy in Kabul denied there had been any shouting or that Holbrooke had stormed out, the BBC said Thursday.

The tense meeting, held on the day after the poll, was said to have been noticeably briefer than a discussion Holbrooke held with Karzai's main rival for president, Abdullah Abdullah.