Americans detained for years in Iran arrived home on Tuesday, tearfully hugged their loved ones and declared “Freedom!” after being let go as part of a politically risky deal that saw Joe Biden agree to the release of nearly $6bn in frozen Iranian assets. The prisoners landed at Fort Belvoir, Virginia, with clapping and cheers heard in the pre-dawn hours. Siamak Namazi, the first off the jet, paused for a moment, closed his eyes and took a deep breath before leaving the plane. Loved ones, some holding small American flags, enveloped them in hugs and exchanged greetings in English and Farsi, the main language of Iran. “The nightmare is finally over,” Namazi’s brother, Babak, said at the airport. The former prisoners later posed for a group photograph with their families, calling out: “Freedom!” The successful negotiations for the Americans’ freedom brought Biden profuse thanks from their families but heat from Republican presidential rivals and other opponents for the monetary arrangement with one of America’s top adversaries. Iran’s hardline president, Ebrahim Raisi, on hand for the UN general assembly in New York, suggested the exchange could be “a step in the direction of a humanitarian action between us and America”. “It can definitely help in building trust,” Raisi told journalists. However, tensions are almost certain to remain high between the US and Iran, which are locked in disputes over Tehran’s nuclear program and other matters. Iran says the program is peaceful, but it now enriches uranium closer than ever to weapons-grade levels. The prisoner release unfolded amid a major American military buildup in the Persian Gulf, with the possibility of US troops boarding and guarding commercial ships in the strait of Hormuz, through which 20% of all oil shipments pass. After the plane slowed to a stop in Doha, three of the prisoners – Siamak Namazi, Emad Sharghi and Morad Tahbaz – emerged. In a statement issued on his behalf, Namazi said: “I would not be free today, if it wasn’t for all of you who didn’t allow the world to forget me.” The United States did not immediately identify the other two freed Americans. All were released in exchange for five Iranians in US custody and for the deal over the frozen Iranian assets owed by South Korea. The Biden administration said the five freed Iranians pose no threat to US national security. Two of the imprisoned Americans’ family members, Effie Namazi and Vida Tahbaz, who had been under travel bans in Iran, were also on the plane. The Iranian foreign ministry spokesman, Nasser Kanaani, said two of the Iranian prisoners would stay in the US. Meanwhile, Nour News, a website believed to be close to Iran’s security apparatus, said two of the Iranian prisoners were in Doha for the swap. Nour News identified the two in Doha as: Mehrdad Ansari, an Iranian sentenced by the US to 63 months in prison in 2021 for obtaining equipment that could be used in missiles, electronic warfare, nuclear weapons and other military gear, and Reza Sarhangpour Kafrani, an Iranian charged in 2021 over allegedly unlawfully exporting laboratory equipment to Iran. The $5.9bn in cash released to Iran represents money South Korea owed Iran – but had not yet paid – for oil purchased before the US imposed sanctions on such transactions in 2019. The deal has already opened Biden to fresh criticism from Republicans and others who say the administration is helping boost the Iranian economy at a time when Iran poses a growing threat to American troops and Middle East allies. In his statement, Biden demanded more information on what happened to Bob Levinson, an American who went missing years ago. The Biden administration also announced fresh sanctions on the former Iranian president Mahmoud Ahmadinejad and the Iranian ministry of intelligence. The US government, the prisoners’ families and activists have denounced the charges against the five Americans as baseless. The Americans included Namazi, who was detained in 2015 and later sentenced to 10 years in prison on spying charges; Sharghi, a venture capitalist sentenced to 10 years; and Tahbaz, a British-American conservationist of Iranian descent who was arrested in 2018 and also received a 10-year sentence. In a statement, Sharghi’s sister, Neda, said she “can’t wait to hug my brother and never let him go”.