The Obama administration spent three years engaged in secret talks with Iran that resulted in the payment of $1.7 billion in taxpayer funds to Iran, with more future payouts likely, according to a U.S. State Department letter obtained this week by the Washington Free Beacon.

The payment was revealed due to an inquiry launched by U.S. Rep. Mike Pompeo (R-Kan.) in January. The Washington Free Beacon reported that many viewed the payment as “ransom” for Iran’s release of several American hostages.

The Obama administration did not respond to Pompeo until this week, when State Department Assistant Secretary for Legislative Affairs Julia Frifield wrote that more taxpayer-funded financial transfers are likely in order to settle decades-old Iranian legal claims against the U.S.

“We are confident that this was a good settlement for the American taxpayer,” Frifield wrote.

Iran’s legal disputes with the U.S. stem from the breakdown of a major weapons deal that was cancelled following the 1979 Islamic Revolution in Iran.

Many claims are still being litigated by the Iran-U.S. Claims Tribunal at The Hague, the Washington Free Beacon report said.

“The United States is continuing to vigorously litigate these claims at the tribunal, but is also open to discussing further settlements of claims with Iran, as we have done throughout the life of the tribunal, with the aim of resolving them in furtherance of U.S. interests,” Frifield wrote.