Iran's Supreme Leader Ayatollah Ali Khamenei said claims that opposition leaders had links to Western powers have not been proven despite widespread allegations of foreign meddling by hard-liners. The comments late Wednesday appeared to mark a significant shift away from the assertions of others in the Islamic leadership, including President Mahmoud Ahmadinejad, that the United States, Britain and other nations had a direct hand in guiding the violence and outrage following the disputed June 12 elections. It also could spill over into the trials of more than 100 pro-reform activists and politicians, including some who have offered statements saying foreign agents helped stoke Iran's worst internal unrest since the 1979 Islamic Revolution. Rights groups and others say the public confessions were coerced by threats and abuse in custody. Speaking to a group of students on Wednesday night, Khamenei said: "I do not accuse leaders of the recent events of being stooges of aliens including the US and Britain, since it was not proved for me." But Khamenei - who has final say on all state matters - added that the post-election unrest was calculated by Iran's enemies "whether or not its leaders know," and rebuked the opposition leaders for calling attention to alleged abuses of detainees. Ahmadinejad and others, including senior commanders in the Revolutionary Guard, have suggested that Western nations had direct links to opposition leaders such as former parliament speaker Mehdi Karroubi and Mir Hossein Mousavi, who claims that massive vote rigging deprived him of victory in the June election. Khamenei has backed Ahmadinejad throughout the turmoil, but it has come at a price. The post-election crisis has shattered taboos about open criticism of Khamenei and his all-powerful role. On Wednesday, Iran's most senior dissident cleric Grand Ayatollah Hossein Ali Montazeri described the ruling system under Khamenei as a dictatorship. "The biggest oppression... is despotic treatment of the people in the name of Islam," Montazeri was quoted as saying. Without directly naming opposition leaders, Khamenei criticized them for highlighting claims of abuses in Kahrizak prison, one of the sites holding the detained protesters. "Some ignore defacing of the system while highlighting the issue of Kahrizak," Khamenei was quoted as saying by the state Islamic Republic News Agency. "This way of thinking is an open unfairness." Karroubi and others have demanded investigations into allegations of torture and rape against security agents.