The State Department has said a plane filled with $400 million in cash for Iran was “leverage” to ensure that five American prisoners held by Iran were released. Republicans, including Donald Trump, have said the money was a ransom for the prisoners. The money was sent to Iran in January. The Obama administration has said the money was a pre-planned transfer that was part of the landmark nuclear deal and that the negotiations regarding the two issues were separate. But State Department spokesperson John Kirby has now said the money’s delivery was held up because of concern Iran would not fulfill its end of the agreement.

John Kirby: “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. As we said at the time, we deliberately leveraged that moment to finalize these outstanding issues nearly simultaneously.”

The money has been owed to Iran since the 1970s, when the U.S. refused to send weapons Iran had already paid for following the Iranian revolution.