Iranian opposition leader Mir Hossein Musavi's two daughters were briefly held for questioning on Monday, according to the opposition website Kaleme, said Reuters.
Musavi campaigned as a reformist in Iran's 2009 presidential election, and his supporters played a critical role in mass protests that shook the nation after the disputed vote. The unrest was the greatest seen in Iran since the country's 1979 Islamic Revolution, and authorities are closely monitoring opposition movements in the four months leading up to the 2013 June vote.
Ardashir Amir Arjmand, a spokesman for Musavi, told RFE/RL's Radio Farda from Paris that they were not sure why Musavi's 27-year-old daughter Narges and 37-year-old daughter Zahra Musavi, a university professor banned from teaching, had been summoned. There are three daughters in the family, said Farda, and it was not immediately clear why only two were taken in for questioning.
"Security forces raided the home of Zahra and Narges, and arrested them in the morning," Agence-France Press cited the Kaleme report as saying.
Iranian officials cited by local media said they were asked "to give some explanation," but did not clarify further. Seventy-year-old Musavi, who served as prime minister in the 1980s, is currently under house arrest along with his wife.
Arjmand told Farda that the couple's family "have been under pressure by security forces for quite a long time" and have been "repeatedly threatened."
The sisters have campaigned for their parents' release in the past.