WASHINGTON (Reuters) - The family of an Iranian-American jailed in Tehran and his father, who is unable to leave Iran, urged U.S. President Joe Biden on Monday to make their freedom a precondition of any deals between the United States and Iran. A top White House official said on Sunday the United States had begun to communicate with Iran over its detention of Americans. The move coincides with the Biden administration seeks talks with Iran on reviving a 2015 deal with global powers that aims to stop Iran from developing a nuclear weapon. Iran’s Revolutionary Guards have arrested dozens of dual nationals and foreigners, including several Americans, in recent years, mostly on espionage charges. Rights activists accuse the country of trying to use the detentions to win concessions from other countries, though Tehran dismisses the charge. Siamak Namazi, an Iranian-American businessman in his mid-40s, was arrested by Iranian security forces in October 2015. Iranian authorities detained Baquer Namazi, 84, a few months later when he tried to visit his son. “My family expects that President Biden and his administration will not make concessions or deals with Iran that do not include, that indeed requires (as) a precondition the release of my father and Siamak,” Babak Namazi told an online news conference. The pair were sentenced in October 2016 to 10 years in prison on charges of collaborating with “a hostile government” - the United States. The family denies the allegations and considers the pair “hostages,” Babak Namazi said. Simak Namazi is in Tehran’s notorious Evin Prison. Babak Namazi said his father - who underwent triple bypass surgery before he was detained and heart surgery while jailed - was released from the prison on medical furlough in 2018 and had his sentence commuted to time served in 2020. But Babak Namazi said his father was unable to leave Iran for urgent medical treatment because he has been denied a new passport and remained under a travel ban. “It is beyond outrageous that Iran continues to play with my father’s life,” he said. Iran said on Sunday that communication between Tehran and Washington about U.S. citizens detained in Iran had been conducted via the Swiss embassy that handles U.S. interests rather than through direct contact.