(Adds background on Saturday meeting)
TEHRAN, June 19 Defeated presidential candidate Mehdi Karoubi called on Friday for Iran's election result to be cancelled, hours after Supreme Leader Ayatollah Ali Khamenei endorsed the victory of President Mahmoud Ahmadinejad.
In an open letter which will be delivered to the country's highest legislative body, the Guardian Council, on Saturday, Karoubi said: "Accept the Iranian nation's will by cancelling the vote and guarantee the establishment's survival."
The letter was published on Karoubi's website.
The Guardian Council is considering complaints by the three losing candidates, but has said only that it will recount some disputed ballot boxes, rather than annul the vote as demanded by Ahmadinejad's main challenger, Mirhossein Mousavi.
The council has invited Mousavi, Karoubi and the other defeated candidate Mohsen Rezaie to an extraordinary meeting on Saturday morning.
Khamenei said in his speech any complaints should be raised through legal channels, dismissing charges of fraud. "Iran's laws do not allow vote-rigging, especially at the level of 11 million," he said, referring to Ahmadinejad's victory margin.
He also said defeated candidates were wrong to believe "that by using street protests as a pressure tool, they can compel officials to accept their illegal demands. This would be the start of a dictatorship."
(Tehran newsroom +98 820 8770)