Two Republican presidential candidates campaigning in Iowa today are raising concerns about a “prisoner swap” with Iran. New Jersey Governor Chris Christie started a “town hall” meeting in Ames late this morning by talking about Iran’s release of four Americans with dual citizenship in Iran who’ve been imprisoned there.

“We’re all grateful…that the Iranians have released our Americans,” Christie said, getting a round of applause from the crowd. “…The concern I have, and we don’t know yet, is the president made a trade.”

Several news agencies report a Washington Post journalist, a Christian pastor, a former Marine and an American businessman are being released. Christie said those Americans shouldn’t have been under arrest in Iran in the first place and the U.S. “shouldn’t have to trade anything to get our citizens back home.”

“When this president makes trades, this is a big problem,” Christie said. “This is not a guy I would let negotiate buying a car for me, let alone anything else. I mean, he makes bad deals and he seems to become an expert at making bad deals with the Iranians.”

The deal needs to be “scrutinized”, according to Christie.

“If we had a president who was respected around the world, we wouldn’t have these folks taken in the first place,” Christie said. “Remember the last time we had Iranian hostages? Again, a president that the world did not respect in Jimmy Carter and as soon as Ronald Reagan took the oath of office, those Iranians returned our citizens immediately.”

The prisoner swap happened just before the deal that lifts economic sanctions against Iran is set to go into effect. Florida Senator Marco denounced the deal during an appearance early this morning in Johnston, before many details of the prisoner swap were known.

“Iran is going to get $100 billion of sanctions relief, which they’ll use to build a weapon,” Rubio said, “and, by the way, continue to be aggressive against us.”

After the event, Rubio told reporters the U.S. should “never” be involved in “prisoner swaps” because they provide an incentive to people “to take Americans hostage…even if they’ve done nothing wrong.” President Obama has reportedly granted clemency to seven Iranians who’ve either been convicted or are set to go on trial in the United States.