The American prisoners include Siamak Namazi, Emad Sharghi and Morad Tahbaz, who the U.S.

 The American prisoners include Siamak Namazi, Emad Sharghi and Morad Tahbaz, who the U.S.

 Government says were all wrongfully detained on bogus spying charges. The names of the other two were being withheld by their families, but one is said to be a scientist, the other a businessman. 

In a statement released Thursday, National Security Council spokesperson Adrienne Watson said that while the move to house arrest is an "encouraging step," negotiations for their eventual release remain "ongoing and are delicate."

"These U.S. Citizens — Siamak Namazi, Morad Tahbaz, Emad Shargi, and two Americans who at this time wish to remain private — should have never been detained in the first place," Watson said.

"We will continue to monitor their condition as closely as possible. Of course, we will not rest until they are all back home in the United States," the statement added. "Until that time, negotiations for their eventual release remain ongoing and are delicate. We will, therefore, have little in the way of details to provide about the state of their house arrest or about our efforts to secure their freedom." 

U.S. President Joe Biden speaks during a State of the Union address at the US Capitol in Washington, DC. The Biden administration reached a prisoner swap deal with Iran on Thursday. (Photographer: Jacquelyn Martin/AP/Bloomberg via Getty Images)