According to the UK Telegraph, leaked election results, Ahmadinejad actually came in third place (emphasis mine).
Supporters had been due to turn out en masse in Tehran on Monday afternoon, despite government warnings to stay off the streets.
But this morning, a statement on Mr Mousavi’s campaign website announced that the demonstration had been postponed – although it said Mr Mousavi would go to the site to ensure any supporters who showed up remained calm.
Mr Mousavi’s wife and co-campaigner, Zahra Ranavard, was reported as warning that riot squads would be equipped with live ammunition, raising the prospect of serious bloodshed.
Iran’s Interior Ministry said Mr Mousavi would be responsible for any consequences if he went ahead with the protest.
Mr Mousavi’s cancellation of the protest came as sporadic disturbances continued around the Iranian capital, and reports circulated of leaked interior ministry statistics showing him as the clear victor in last Friday’s polls.
The statistics, circulated on Iranian blogs and websites, claimed Mr Mousavi had won 19.1 million votes while Mahmoud Ahmadinejad had won only 5.7 million.
The two other candidates, reformist Mehdi Karoubi and hardliner Mohsen Rezai, won 13.4 million and 3.7 million respectively. The authenticity of the leaked figures could not be confirmed.
This is in contrast to a Washington Post article that says Ahmadinejad’s election was legitimate because it reflected a poll the Post conducted several weeks before the election.