Several of its members have been jailed in the election aftermath along with scores of reformist leaders, journalists and political activists.
Meanwhile the editor of a Mousavi campaign newspaper accused him of 'causing' the death of Iranians in protests, local media reported.
Amir Hossein Mahdavi, 27, told reporters gathered at ISNA news agency he was also a member of the Islamic Revolution Mojahedeen Organisation - one of the key reformist groups that backed Mr Mousavi for the election.
'Now that Mr Mousavi's stirring statements have caused the killing of some compatriots he is trapped' by his misjudgment, said Mr Mahdavi, who edited Andisheh No, a four-page newspaper dedicated to covering the moderate candidate's campaign.
However, leading cleric Grand Ayatollah Abdol Karim Mousavi Ardebili said the 'solution to prevent such protests spreading in the streets is to give demonstrators a channel, 'either through television or legal gatherings, ILNA news agency reported.
Mr Ahmadinejad unleashed a new tirade against US President Barack Obama, saying: 'He who spoke of reforms and changes, why did he interfere and comment in a way that disregards convention and courtesy?' On Friday, Mr Obama said Iran's 'outrageous' crackdown on demonstrators would hit his hopes for direct talks with Iran.
'There is no doubt that any direct dialogue or diplomacy with Iran is going to be affected by the events of the last several weeks,' Mr Obama said, referring to the deadly clashes between security forces and demonstrators protesting what they claim was Mr Ahmadinejad's fraudulent re-election.
However, Mr Obama said talks between Iran and the five veto-wielding permanent members of the UN Security Council plus Germany over its nuclear programme are likely to continue.
The United States and other Western countries suspect Iran of using its nuclear energy programme as cover for a drive for an atomic weapon. Teheran denies that, saying its aims are purely civilian.
On Friday, foreign ministers of the Group of Eight leading powers said they were 'concerned about the aftermath of the Iranian presidential election.
'We fully respect the sovereignty of Iran. At the same time we deplore post-election violence which led to the loss of lives of Iranian civilians and urge Iran to respect fundamental human rights.
Iran regrets the 'interfering and hasty position' taken by the G8 ministers, foreign ministry spokesman Hassan Ghashghavi said. -- AFP