The United States has criticized Iran's detention of two opposition leaders as "unacceptable" and called for their release.
White House spokesman Jay Carney made the comments Monday, after an Iranian opposition website said authorities had transferred opposition leaders Mir Hossein Mousavi, Mehdi Karroubi and their wives to a Tehran prison.
Iran's government put the two prominent reformists under house arrest after they called for opposition rallies on February 14 in solidarity with anti-government uprisings in the Arab world. Iran's government banned the rallies and ordered security forces to disperse them, triggering violence that killed two people.
Iran's semi-official Fars news agency says a judicial official denied the opposition's claim that Mousavi and Karroubi were moved to Tehran's Heshmatieh prison. The official said Monday authorities have kept the two men under house arrest and restricted their contacts with the outside world.
Iranian opposition activists have called for protests to be held every Tuesday to demand the release of the leading reformists.
U.S. Secretary of State Hillary Clinton also criticized Iran Monday, accusing it of carrying out a systematic crackdown on the opposition. She called for Tehran to show transparency on alleged human rights violations.
Some information for this report was provided by AP, AFP and Reuters.