WASHINGTON (AP) — The State Department says a $400 million cash payment to Iran was contingent on the release of American prisoners.

Spokesman John Kirby says negotiations over the United States’ returning Iranian money from a decades-old account was conducted separately from the prisoner talks. But he says the U.S. withheld delivery of the cash as leverage until the U.S. citizens had left Iran.

Both events occurred Jan. 17.

Kirby spoke after The Wall Street Journal reported that the departures of the crisscrossing planes were linked.