Iran's public prosecutor has summoned for questioning two daughters of opposition figure Mir Hossein Mousavi, who has been under house arrest for nearly two years, the ISNA news agency reported on Monday.
"They were summoned... to give some explanations," ISNA quoted a spokesman for the prosecutor as saying, without giving details on the questioning. He said Zahra and Narges Mousavi would be released after their interrogation.
A statement on the prosecutor's website denied an earlier report that the sisters had been arrested.
Kaleme.com, a website close to Mousavi, had reported the sisters had been arrested by security forces who raided their house.
Mousavi's oldest daughter, Kokab, confirmed that her sisters were summoned for questioning and told Kaleme.com that Narges had "been told that she has to answer some questions."
Mousavi was a leading figure behind opposition protests against the result of the 2009 presidential election, which gave President Mahmoud Ahmadinejad a second four-year term.
Mousavi and fellow reformist candidate Mehdi Karroubi charged the election was rigged and guided a string of protests against Ahmadinejad.
The pair -- branded by authorities as "leaders of the sedition" which sought to overthrow the government after the election -- have both been kept under house arrest since February 2011.
The latest developments come as Iran prepares to hold June presidential polls to elect a successor for Ahmadinejad, who cannot run for a third consecutive term under Iranian law.