Iran's opposition leader Mir Hossein Mousavi says he will continue his struggle against the government.
In a statement posted on his website, Mr Mousavi says the 1979 Islamic revolution has failed to achieve most of its goals.
He said it had failed to eradicate the roots of tyranny and dictatorship that marked the Shah's era.
Mr Mousavi says politically motivated arrests of protesters are illegal and more should be done to secure people's rights.
The BBC reports his comments constitute one of his strongest challenges to the government.