An Iranian website says the country's main opposition leader, Mir Hossein Musavi, has returned home from hospital after several days of treatment.
The opposition Kaleme.org website reported that Musavi, who has been under house arrest since 2011, was discharged from a Tehran hospital after receiving treatment for a heart problem.
No further details were given.
Musavi, 71, has previously been treated for heart problems and high-blood pressure.
Musavi and another reformist leader who is also under house arrest, Mehdi Karrubi, ran against former President Mahmud Ahmadinejad in the 2009 presidential election.
Reformists claimed Ahmadinejad's victory was rigged and supporters staged mass protests that were crushed by authorities.
Based on reporting by Kaleme.org and AP