Even as Americans welcomed Iran's release of four American prisoners, at least three Republican presidential candidates—Ted Cruz, Marco Rubio and Donald Trump—on Sunday lambasted the prisoner exchange this weekend between the U.S. and Iran, saying the Obama administration negotiated "with terrorists."

"Our enemies are laughing at us," Cruz said on "Fox News Sunday."

The deal announced Saturday saw Iran releasing four American detainees—Washington Post reporter Jason Rezaian, Pastor Saeed Abedini, former U.S. Marine Amir Hekmati and Nosratollah Khosravi—in exchange for the release of seven Iranians, whom Cruz said were detained for trying to help Iran with its nuclear programme.

U.S. officials said the Iranians who were set free had no terrorist or criminal links and had already been offered clemency.

Cruz disagreed with this assessment, saying, "They tried to kill us."

U.S. officials also announced on Saturday that a fifth American, student Matthew Trevithick, was also freed but that his release was unrelated to the swap.

"Praise God, Americans are coming home, but this deal is really problematic," said Cruz, who is trailing front-running GOP presidential candidate Donald Trump in national polls but leading in Iowa.

Cruz also warned that the prisoner swap sets a "dangerous precedent," meaning other anti-American regimes could likewise capture and detain Americans and hold them for ransom.

Rubio also criticised the latest deal, saying the U.S. should never engage in prisoner "swaps," Raw Story reported.

"If these reports are true, of course we're happy for them and their families, but they should have never been there," Rubio said. "The fact of the matter is that this tells us everything we need to know about the Iranian regime—that they take people hostage in order to gain concessions. And the fact that they can get away with it with this administration I think has created an incentive for more governments to do this around the world."

Trump also pooh-poohed the deal, saying, "Meh, doesn't sound too good."

"I have to see what the deal is for the four people, because somebody said they're getting seven people back," Trump said. "So essentially they get 150 billion plus seven, and we get four. Meh, doesn't sound too good. Doesn't sound too good."