Iran's supreme leader Ayatollah Ali Khamanei has warned against any bid to end the house arrest of two top opposition leaders, a champion of their release told Iranian media Monday.
Lawmaker Ali Motahari, a supporter of President Hassan Rouhani, said Khamanei had told him the house arrest imposed on the two defeated 2009 presidential election candidates was a "favour" and that they would face far worse punishment if they stood trial.
The two candidates -- Mir Hossein Mousavi and Mehdi Karroubi -- both regime insiders turned critics -- have been kept incommunicado since February 2011 after leading months of protests alleging fraud in their defeat by Rouhani's hardline predecessor Mahmoud Ahmadinejad.
Their continued house arrest has presented a dilemma for Rouhani, a professed moderate whose administration has promised to move to resolve the issue since assuming power last August.
Motahari said that he had urged their release in a brief June 17 conversation with Khamenei, who has the final say in all matters of state in Iran.
"In my opinion and many others, the continuation of the house arrest of Mousavi and Karroubi is not to the benefit of the country and the revolution and is unnecessary," the MP said he had told the supreme leader.
"I request your excellency to order the judiciary to end this."
Motahari said that Khamenei had retorted that the treatment of the two men had been more than fair.
"If they are tried, their sentence will be very heavy and you certainly will not be satisfied," he quoted the supreme leader as saying.
"We are currently doing them a favour."
UN chief Ban Ki-moon and Western governments have repeatedly urged Iran to release Mousavi and Karroubi.
But the issue remains a deeply sensitive one in Iran that polarises moderate and conservative opinion within the regime.