Secretary of State John Kerry reaffirmed President Obama's intention to impose new sanctions on Iran for conducting illegal ballistic missile tests in recent months.

"The president always has the prerogative to choose the timing of what he does, but he made clear he would enforce those sanctions and he will," Kerry told CNN's Wolf Blitzer Monday evening.

Reacting to Tehran's ballistic missile tests, conducted in October and November, the Obama administration in December told key members of Congress it planned to level sanctions on Iran for violating United Nations resolutions, but then reversed itself without explanation.

Kerry Monday conceded that Obama made the decision to hold off on the sanctions in December because of the sensitive nature of the process of verifying that Tehran was complying with the separate nuclear deal before the U.S. would lift sanctions on implementation day, which occurred over the weekend. He also suggested that the negotiations to release three American hostages could have played a role in holding off on the sanctions.

"I think it's fair to say that we wanted to respect the sensitivity of everything we were doing," Kerry said. "But we made it clear that we were going to do it. We made it clear weeks ago [when we] notified Congress."

Kerry also insisted that the release of the four Americans in exchange for the United States pardoning or commuting the sentences of an Iranian and six dual citizens of the United States and Iran was not linked to the nuclear deal, and the timing of the prisoner swap, on the same weekend as implementation day, was merely coincidental.

"We really almost had an agreement well before implementation day, and it got caught up in a snag of interpretation," he said. "We had to work it through, and then it simply dovetailed in [with implementation day] and dovetailed fairly easily but it was not linked."

In the end, the administration knew that the timing of the prisoner swap and the sanctions relief would come at the same time, he said.

"In the last weeks it became almost automatic that this was all going to happen in one fail swoop but it was not linked for a year and a half," he said.

Kerry said he didn't know if any of the three Americans — Washington Post journalist Jason Rezaian, Marine veteran Amir Hekmati and Christian pastor Saeed Abedini — had been tortured.

"I haven't had the debrief yet," he said. "They're being evaluated at the hospital at Landstuhl," Germany.

Kerry also refused to confirm reports that he was so upset about the Iranian detention of 10 U.S. sailors last week that he got into a threatening yelling match with Iranian officials.

"I don't want to get into the precise language. I think that inappropriate," he said. "I made it clear that I was extremely upset and frustrated and that [the sailors' capture was inappropriate. I made I clear to the Iranians that we needed those people back, and we needed them right away."

He said that his counterpart, Iranian Foreign Minister Mohammed Javad Zarif, responded promptly and "could not have been more serious."

"He understood the gravity of the situation," he said, crediting the sailors' prompt release to the Obama administration's diplomatic engagement that resulted in the nuclear deal.

"Within a matter of a few hours we did what could not have been done three years ago. We wouldn't have known who to call three years ago — maybe the Swiss, maybe the British," he said. "That could have become a major hostage situation and could have been very, very dangerous but because we have a channel of communication, because we worked on this nuclear agreement, we were able to resolve this."

Kerry declined to comment on Donald Trump's criticism on the campaign trail of his negotiating skills.

"I'll let the process take care of itself. I'm not involved in the presidential race," he said. "I prefer to keep focused on the job that I am doing."