At least ten Afghan civilians have been killed along with six Italian troops in a suicide car bomb that struck an Italian convoy on a busy central Kabul road.
Defence Ministry spokesman Zaher Azimy said 52 civilians were wounded in the explosion.
Earlier, Afghan President Hamid Karzai, who according to preliminary results is set to win the recent presidential election, denied that fraud took place.
His comments come amid mounting allegations of vote-rigging in last month's landmark elections.
A statement issued by EU observers said they have doubts about one quarter of the votes cast, describing 1.5m as suspicious.
Mr Karzai, who denies the allegations, today called for a 'fair and unprejudiced' investigation into cases of suspected electoral fraud.
'Fraud, if it were conducted, it has to be investigated, and investigated fairly, and without prejudice,' he told reporters.
