Iran's judiciary has concluded investigations into two detained Iranian-Americans accused of conspiring to destabilize the country, a top judiciary official said. But no decision has been made on whether they will be put on trial, he said.

"The investigation into Haleh Esfandiari and Kian Tajbakhsh is over," said Tehran Deputy Prosecutor Hasan Haddad said Sunday, according to the official IRNA news agency. "The two have some written work to do. Then, a decision will be taken about them."

Haddad did not explain what written work would be required from the two scholars, who have been detained since May in Evin prison in Tehran, notorious for holding political prisoners incommunicado.

Esfandiari, director of the Middle East program at the Washington-based Woodrow Wilson International Center for Scholars, and Tajbakhsh, an urban planning consultant with the Soros Foundation's Open Society Institute, are accused of endangering national security.

Iran's public television broadcast last month a video in which Esfandiari said a network of foreign activists was trying to destabilize Iran and bring about "essential" social change. In the video, Tajbakhsh said his organization tried to create a "gap between the government and the nation."

Both the Wilson Center and the Open Society Institute have dismissed the statements as "coerced." Iran has often been criticized for forcing some detainees to incriminate themselves publicly on television.