CAIRO — An opposition website says Iran's main opposition leader who has been under house arrest since 2011 has returned home from hospital after days of medical tests.

It's reportedly the fourth time that Mir Hossein Mousavi has been hospitalized in the past two years.

The report by says doctors allowed Mousavi to return home after "recent days' treatment." There were no details on his condition.

The 71-year-old Mousavi ran against former President Mahmoud Ahmadinejad in the 2009 election. Reformists claimed Ahmadinejad's victory was fraudulent and demonstrations rocked Iran for weeks, after which authorities moved to crush the opposition.

Mousavi and fellow opposition leader Mahdi Karroubi were effectively silenced and placed under house arrest in early 2011.