Iran's Guardian Council offered a partial recount of the presidential vote Tuesday as pressure mounted from the biggest rally since the revolution, in which eight were killed.
Iran's supreme leader ordered the Guardian Council to investigate the candidate's claims of electoral fraud. But the council is headed by a cleric cut from the same cloth as President Ahmadinejad.
Street clashes between security forces and supporters of challenger Mousavi picked up after dark on Sunday after President Ahmadinejad addressed thousands of his supporters in Tehran.
President Mahmoud Ahmadinejad's hard-line allies and other conservative factions are expected to win a majority in the 290-seat parliament.