The Obama administration is conceding that the $400 million cash payment it made to Iran in January was contingent on the release of Iranian-American prisoners. Officials, though, won't call it a "ransom."

The way the administration explains it, there were a lot of moving parts over a 24-hour period: A nuclear deal with Iran was being implemented, the U.S. was trying to get several American prisoners out of the country, and the U.S. was clearing a financial claim dating back to the 1979 Iranian revolution. The $400 million was the first installment of a $1.7 billion settlement that U.S. officials insist was a good deal for U.S. taxpayers. It was Iranian money, plus interest, for an arms deal made before the shah of Iran was toppled.

All that was well-known back in January. What is new in the story is the timing of the payment, as first reported on Wednesday in The Wall Street Journal.

State Department spokesman John Kirby said on Thursday that the cash payment was held up until the American prisoners took off in their plane out of Tehran. He said the U.S. didn't trust Iran, because it was taking longer than expected to gather all the Americans on that flight and officials were worried Iran would renege.

"We of course sought to retain maximum leverage until Americans were released," Kirby said. "That was our priority."

When an Associated Press reporter pointed out that this meets the definition of a quid pro quo, Kirby thanked him for the Latin lesson but rejected that description. And the important thing, Kirby noted, was that the Americans got out.

The political fallout is sure to continue, however. Republican Sen. Marco Rubio of Florida points out that the Iranians saw it as a ransom. "It's a sad day when Iranian officials appear to be more honest than our own president," Rubio wrote in a blistering statement.

Copyright 2016 NPR. To see more, visit http://www.npr.org/.