Leading human rights groups jointly urged Teheran on Thursday to immediately release American-Iranian scholars and activists held by Iran on suspicion of spying and banned from leaving the country. The call came as the United States confirmed Thursday that Iran is holding four dual US-Iranian nationals in custody in Teheran's notorious Evin Prison. The four include Haleh Esfandiari, director of the Middle East Program at the Washington-based Woodrow Wilson Center for Scholars; Kian Tajbakhsh with George Soros' Open Society Institute; journalist Parnaz Azima from the US-funded Radio Farda; and Ali Shakeri, a peace activist and founding board member at the University of California, Irvine's Center for Citizen Peacebuilding. In a joint statement, London-based Amnesty International, Human Rights Watch in New York, Reporters without Borders from Paris, the International Federation for Human Rights and 2003 Nobel Peace Prize laureate Shirin Ebadi, urged Iran to stop "harassment of dual nationals." The detentions were an "attempt by Iran's security authorities to sow fear into the wider community of journalists, writers, scholars and activists," said the statement, made available to The Associated Press in Cairo.