Washington - A month after Iranian officials said they would soon free an Iranian-American radio reporter Roxana Saberi, Washington was still trying to obtain her release, a US official said Monday.

Saberi has been detained since the end of January in Tehran's Evin prison.

"We continue to work to try to get her released," US State Department deputy spokesman Robert Wood said.

The release of Saberi and an inquiry about the long-missing US citizen Robert Levinson, a former agent with the US Federal Bureau of Investigation, were the subjects of a letter given to the Iranians last week by US Secretary of State Hillary Rodham Clinton.

"The secretary in her letter ... to the Iranians made very clear that we were concerned about (the Saberi) case and wanted to see it resolved," Wood said.

Wood also called for the release of another Iranian detainee, Sylva Hartounian, an Iranian citizen of Armenian descent and employee of the nongovernmental International Research and Exchanges Board (IREX).

She was helping to administer an exchange programme on maternal and infant health in Iran, IREX said online.

Hartounian was arrested on June 26, 2008, in Iran and "reportedly charged with unspecified activities" related to promoting the "so- called Velvet Revolution in Iran," Wood said. He said that Hartounian has been sentenced to three years in prison, and that she suffers from "poor and deteriorating health."

Wood said the charges against her were "baseless."

"We call on Iran's leadership to release Ms Hartounian," he said.

IREX, which receives money from the US government, the European Commission, Britain, the United Nations and private donors, says it provides leadership for initiative such as improving education, strengthening of independent media and fostering "pluralistic civil society development." (dpa)