(Amends sourcing in first paragraph)
DUBAI, July 30 (Reuters) - An Iranian-American man detained along with three journalists in Iran last week has been released, a source close to one of those being held said on Wednesday.
The United States has called for their release and a senior U.S. official said Washington was using "all appropriate channels" to make its concerns known to Iran.
"They were treated with respect, given food and water," said the source, adding that the man, who is the husband of one of the three detained journalists, was not tortured. Their names are being withheld at the request of the couple's relatives.
Still in detention along with the freed man's wife, who is an Iranian-American photographer, are Jason Rezaian, 38, an Iranian-American and Tehran correspondent for the Washington Post, and his wife Yeganeh Salehi, a correspondent for the United Arab Emirates-based newspaper The National.
The four were arrested in Tehran last Tuesday.
During a raid on the home of Rezaian and Salehi, security forces "ransacked their house and confiscated their personal items, including computers, books, and notes," according to the International Campaign for Human Rights in Iran, a New York-based human rights organization.
"We are very worried about them ... haven't heard from them in eight days," Fatemeh Talaee, the mother of Salehi, told Reuters. "We have the right to know where they are and why they were detained," she said, speaking by phone from Tehran.
In a video message posted on the Washington Post's website on Tuesday, Mary Rezaian, Rezaian's mother, expressed worry that her son, who suffers from high blood pressure, does not have access to his regular medication.
Iran confirmed the arrests on Friday and said they were investigating but has not made any announcements since.
Iran does not recognize dual citizenship. Two of the three in detention are dual nationals. There are 35 journalists in prison in Iran, according to the Committee to Protect Journalists (CPJ). (Reporting By Michelle Moghtader; Editing by William Maclean, Raissa Kasolowsky and Kevin Liffey)