The White House's top spokesman indicated Monday that he disagrees with the way the State Department's press secretary described the impact of a $400 million payment to Iran on the release of American prisoners held there, and insisted that it was not used to provide "leverage" for the Americans' safe return.

For the first time last week, State Department spokesman John Kirby said withholding the $400 million until Tehran released the prisoners provided "leverage," although he insisted that there were "multiple strands of diplomacy" taking place within a 24-hour period.

Both the White House and State argue that the payment wasn't "ransom." But under heavy questioning Monday, White House press secretary Josh Earnest stressed that he has never used the word "leverage," and said the prisoners' release was separate from the $400 million payment to settle a long-standing financial dispute with Iran.

"It's not a word I've used so you could ask someone else," Earnest told reporters Monday during his daily briefing in an apparent reference to Kirby.

On Thursday, Kirby twice used a version of the word "leverage" to describe the timing of the $400 million payment.

"We were able to conclude multiple strands of diplomacy within a 24-hour period, including implementation of the nuclear deal, the prisoner talks, and the settlement of an outstanding Hague Tribunal claim, which saved American taxpayers potentially billions of dollars," he said. "As we said at the time, we deliberately leveraged that moment to finalize these outstanding issues nearly simultaneously."

The administration, he said, had concerns that Iran may "renege" on the prisoner release "given unnecessary delays regarding persons in Iran who could not be located as well as, to be quite honest, mutual mistrust between Iran and the United States."

"And the United States, we, of course, sought to retain maximum leverage until after American citizens were released," he continued. "That was our top priority."

While Earnest never used the word "leverage," he agreed that the U.S. was "much more concerned about completing the [prisoner] agreement than we were in reaching the financial settlement."

"The Iranians may have had different priorities," he added.

Earnest also made the point that Obama's national security team unanimously agreed with the parameters of the prisoner exchange with Iran that involved the cash payment to settle a separate dispute.

"I think you won't be surprised to hear that I won't get into a lot of the discussions" involved in the negotiations with Tehran to return Americans held prisoner there, he said. "The president of course discussed these arrangements with members of his national security team, and there was unanimous agreement among his national security team that he should move forward."

Earnest said the Obama administration's position has not changed since early August when a Wall Street Journal report revealed new details about the payment and the prisoner release.

He said the prisoner exchange was "on a separate track" than the negotiations to resolve a three-decade-old financial dispute "in a way that saved taxpayers potentially billions of dollars."

Earnest also touted the many benefits of the broader nuclear deal, arguing that it prevents Iran from attaining a nuclear weapon, has been "verified" and was accomplished without "a single shot being fired ... without U.S. troops being deployed."