A number of prominent Iranian activists have written an open letter to United Nations Secretary-General Ban Ki-moon urging him to intervene in the case of detained opposition leaders Mir Hossein Musavi and Mehdi Karrubi, RFE/RL's Radio Farda reports.
The letter, published on March 1 on opposition websites, calls on Ban to use all "international levers" at his disposal to ensure the welfare of Musavi and Karrubi and seek their release from detention.
Iranian officials have denied the men have been arrested or detained.
Their family, friends, and supporters along with the opposition website Kaleme, which is close to Musavi, say he and Karrubi and their wives, Zahra Rahnavard and Fatemeh Karrubi, were taken recently to Heshmatieh prison in Tehran.
The letter states: "The Iranian nation is faced with a regime which has not only trampled on the basic universal human rights of its people, such as freedom of expression, freedom of assembly, and nonviolent protests, but does not even abide by its own constitution."
The signatories of the letter, who include exiled intellectual Abdolali Bazargan and poet Esmail Khoi, hold the Iranian government responsible for the lives of Musavi and Karrubi, leaders of the opposition Green Movement.
Paris-based religious scholar Mohammad-Javad Akbarin, a signatory to the letter, told Radio Farda on March 1 that there is no news about the condition of the two men or the way they have been treated by authorities.
Akbarin added that if they are under arrest, it is illegal, and if they have disappeared, they have been abducted by Iranian authorities.
Iranian Prosecutor-General Gholamhossein Mohseni Ejei denied that the opposition leaders and their wives have been imprisoned, but failed to specify their whereabouts.Read more in Persian here