Tajbakhsh, who works for the Open Society Institute, has been held in Tehran's Evin prison since May for allegedly endangering Iran's national security.
Tajbakhsh told reporters visiting the prison today that no formal charges have been filed against him and that his case is still under investigation.
He also said conditions inside the prison are "fine."
An Iranian Judiciary spokesman who accompanied the media visit, Ali Reza Jamshidi, said charges in fact have been raised against Tajbakhsh, but that he will probably be released within the next few days.
Meanwhile, another Iranian-American facing charges in Iran -- Radio Farda broadcaster Parnaz Azima -- is expected to leave the country in the coming days after authorities returned her passport on September 4. She had been prevented from leaving Iran for about seven months.
Azima, who has been charged with spreading propaganda against the state, has been told that her case remains open and that there will be a court session at an unspecified date.
Iranian authorities recently released on bail another Iranian-American, Haleh Esfandiari, who had been imprisoned for some three months on similar accusations.
Esfandiari is the director of the Middle East Program of the Woodrow Wilson Institute in Washington, D.C. She was charged with involvement in what authorities have described as a U.S. plot aimed at destabilizing the Iranian regime.
In Washington on September 10, Esfandiari told journalists that she was treated well, and with respect, during her detention. She also appealed for greater dialogue between the United States and Iran.
There is no news, however, about Iranian-American Ali Shakeri, a peace activist from California who has also been in jail in Iran since May.