Iran has granted a furlough to imprisoned Iranian-American Siamak Namazi for the first time in seven years, and lifted the travel ban on his elderly father, the U.N. secretary general and the family's lawyer said Saturday.
Iranian authorities gave Namazi a one-week, renewable furlough and he was reunited with his parents in Tehran, his lawyer Jared Genser told NBC News.
"While these are critical first steps, we will not rest until the Namazis can all return to the United States and their long nightmare has finally come to an end," Genser said in a statement.
Siamak Namazi, a businessman who was arrested in 2015, is the longest-held Iranian-American prisoner in Iran. His father, Baquer Namazi, who worked for the United Nations before retiring, was also imprisoned and later released on a medical furlough, but he has remained under a travel ban.
The U.N., the U.S. government and human rights groups say the espionage charges against both of them are baseless and that his detention is a violation of international law. Three other Americans are held in Iran as well as at least one legal permanent resident.
"The secretary-general is grateful that, following his appeals to the president of the Islamic Republic of Iran, our former colleague Baquer Namazi has been permitted to leave Iran for medical treatment abroad," a spokesperson for U.N. Secretary General António Guterres said in a statement.
"The secretary-general is also pleased to learn that Baquer Namazi's son, Siamak Namazi, has been released from detention," the spokesperson added.
The move came as negotiations on reviving a 2015 nuclear deal with Iran have stalled, according to U.S. and European diplomats.
Families and advocates of Americans imprisoned in Iran have called on the Biden administration not to allow their loved ones to remain behind bars even if the nuclear talks collapse, urging the White House to negotiate to secure the Americans' release.
Siamak Namazi recently issued an emotional appeal through his lawyer, saying the administration needed to do more to bring him and other Americans home.
"Gambling the fate of U.S. hostages in Iran on the success of the nuclear talks is negligent & cruel. We must be freed first, & now!" Namazi said in tweets posted by his lawyer.
Iran's U.N. mission did not immediately respond to a request for comment.
This article was originally published on NBCNews.com