The U.S. prisoner swap deal with Iran announced on Saturday and the lifting of sanctions on Iran as the implementation of the nuclear deal took effect prompted the 2016 presidential candidates to welcome the release of the 4 U.S. prisoners, but also criticize the process. Republican candidates also took the opportunity to lambaste the nuclear deal.

Hillary Clinton joined the many skeptics of Iran’s behavior and the concern that the ayatollah may test the U.S. and the world on a later date.

In a statement issued on Saturday, Clinton welcomed the full implementation of the nuclear agreement, “an important achievement of diplomacy backed by pressure.” However, based on Iran’s current behavior, Clinton called on the U.S. to impose additional sanctions on Iran’s non-nuclear activity. “Iran is still violating UN Security Council resolutions with its ballistic missile program, which should be met with new sanctions designations and firm resolve,” she said. “So we can’t take our eye off the ball.”

“As President, my approach will be to distrust and verify. I will vigorously enforce the nuclear deal as part of a comprehensive strategy that confronts all of Iran’s negative actions in the region and stand side-by-side with our ally Israel and our Arab partners,” the Democratic presidential front-runner pledged.

Republican presidential candidate Marco Rubio welcomed the prisoners coming home but criticized the trade deal in an Op-Ed penned for Red State. “We rejoice at the return home of any American who has been unjustly imprisoned, but trading criminals for pastors, journalists, or students who committed no crime sends the wrong message to America’s adversaries the world over,” said Rubio. “This nuclear deal and the appeasement that has accompanied it will not improve Iranian behavior. Just the opposite—it rewards bad behavior. It teaches the world a simple lesson: when challenged, America backs down and abandons its allies.”

According to Rubio, “fueling Iran’s regional ambitions and its support for Assad, as Obama’s policy ends up doing, will only cause ISIS to grow stronger, not weaker. It will also allow Iran to continue to sow unrest in Bahrain, Yemen, Lebanon, and Iraq. It will put more money behind Iran’s efforts to threaten Israel’s security. All of this will leave the world more dangerous if this agreement is left in place.”

“As President, I will start by beginning to undo the flawed nuclear accord on day one. I will restore the sanctions on Iran in every sector: banking, currency, and oil and energy exports, as well as on insurance, automotive, shipping, and precious metals. I will work with Congress to impose crushing new sanctions on the Iranian Revolutionary Guard Corps and Iran’s leadership for its abysmal human rights abuses,” Rubio vowed.

Donald Trump, the GOP’s presidential front-runner, questioned the non-proportional trade deal. “Now I have to see what the deal is for the four people, because someone said they were getting seven back. So essentially, they get 150 billion plus seven, and we get four. Doesn’t sound too good. Doesn’t sound too good,” Trump said during a campaign rally in South Carolina. “I am happy they are coming back, but it is a disgrace they have been there this long, a total disgrace.”

At the same time, Trump sought to take credit for the deal, as he was the one carrying the megaphone on the issue over the past few months. “I have been hitting (the Obama administration) very hard. And I think I might have had something to do with it. You want to know the truth — it’s part of my staple thing — I go crazy when I hear about this,” he said.

New Jersey Governor Chris Christie echoed the sentiment during a town hall meeting in Ames, Iowa. “We have to be grateful that those folks are being sent home but we also have to scrutinize what this president gave away in the process,” 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 deal with the Iranians. The fact is that we shouldn’t have to trade anything to get our citizens back home. They were taken illegally by a rogue regime of Mullahs over in Iran and this is the problem with this president, he gets no respect around the world.”

Former Florida Governor Jeb Bush said during a campaign event in Amherst, New Hampshire, that if he were president, he would have threatened Iran with military action over the prisoners. “I would say … if you do not release them, that there’s going to be military action, that that’s an act of provocation, an act of war. What I would do in January is recognize that Iran is not an ally. That’s how the Obama administration views this,” Bush said. “We need to confront the ambitions of Iran on a broader scale.”

Speaking on the “Fox News Sunday” program, Ted Cruz charged that Obama has allowed the U.S. to be humiliated on the world stage and that the nuclear deal sets a “dangerous precedent” in deterring America’s enemies abroad. “Our enemies are laughing at us,” said Cruz. “It reflects a pattern we’ve seen in the Obama administration over and over again of negotiating with terorrists and making deals and trades that endanger U.S. safety and security.”

“This deal is a really problematic deal and it reflects a pattern we’ve seen in the Obama administration … of negotiating with terrorists and making deals and trades that endanger U.S. safety and security,” he added.

Ben Carson said he was overjoyed for the prisoners’ families, but “the fact remains that President Obama’s nuclear agreement with Iran is fatally flawed and gravely jeopardizes the national security interests of the American people, our ally Israel and other peaceful nations in the Middle East and around the world.”

Rick Santorum remarked, “First, we are returning criminals back to Iran in return for freeing innocent Americans. Under no rational analysis is that a fair deal,” Santorum said in a statement. “Second, this exchange proves that Iran is no friend and continues to get the upper hand in negotiations with the Obama Administration. As I said in Thursday’s debate, Barack Obama’s deal with Iran must be shredded and I intend to do that on day one of my presidency.”

Mike Huckabee and Rand Paul highlighted the release of Iranian-American pastor Saeed Abedini in their statements on the deal.