Congressional Republicans want to censure the Obama administration for sending $400 million in “ransom” to Iran on the same day as American prisoners were released – an issue they bet will play big on the campaign trail two months before election day.

The move comes as new details are emerging about just how and when the Obama administration completed the transfer of $1.7 billion to settle claims related to the incomplete sale of military weapons before the Iranian Revolution in 1979.

According to two congressional aides, Treasury officials said in a Tuesday congressional briefing that after the U.S. made a $400 million cash payment to Iran on Jan. 16 coinciding with the release of four American prisoners, it also paid out the remaining $1.3 billion of interest in cash, in two tranches on Jan. 22 and Feb. 5.

Treasury Department spokesperson Dawn Selak said Tuesday that the payments, “made in non-U.S. currency, in cash,” were necessary because of how successful sanctions have been at isolating Iran from the international financial system over the last several years. According to Treasury officials, the U.S. did not make the cash payments directly to Iran, though the department would not identify international intermediaries.

Republicans have charged that the initial $400 million was nothing more than a “ransom” payment as it coincided with the release of the prisoners, including Washington Post reporter Jason Rezaian. They say the new revelations about the administration’s interest payments are more of the same.

“What’s worse than a $400 million cash ransom to Iran? A $1.7 billion cash ransom to Iran,” House Foreign Affairs Committee Chairman Ed Royce (R-Calif.) said in a statement late Tuesday. “This cash bonanza has emboldened Iran’s radical regime, and undermined America’s national security.”

House GOP leaders are putting a new Iran measure from Royce to prevent such cash payments at the top of their to-do list during the four weeks they are back in session before the November election, with a vote expected in the full House this month.

State Department officials have denied Republican charges that the $400 million  was “ransom,” describing it instead as “leverage” to ensure the Americans were released.

But defining the payment to Iran as “ransom” is one issue on which House Speaker Paul Ryan (R-Wis.) and Donald Trump agree. Ryan said in a statement last month that the payment marked “another chapter in the ongoing saga of misleading the American people to sell this dangerous nuclear deal.”

The GOP presidential nominee memorably claimed that he had seen a grainy video footage of the $400 million in cash being delivered to Iran — he later clarified that the footage he was referring to was of the prisoners on a plane in Geneva, Switzerland. The GOP nominee continued to slam Obama on the subject, however, accusing him of lying about the payment’s purpose.

Republican leaders are coalescing behind a bill Royce introduced Tuesday to censure the Obama administration for the $400 million “ransom,” prohibit any more cash payments from being made to Iran and to ensure that in the future, Congress gets a heads up before any future settlement deals are enacted.

“The Obama administration forked over a massive cash ransom to Iran, emboldening the world’s leading state sponsor of terror and putting more lives at risk,” Royce said in a statement announcing the new legislation. “All of this was done in secret, hidden from the American people and from Congress.  This bill will ensure it doesn’t happen again.”

Royce’s bill comes out the same day as Sen. Marco Rubio (R-Fla.) and Rep. Mike Pompeo (R-Kan.) introduced Republican-backed legislation to stop all future payments to Iran from a fund to pay judgments and settlements against the federal government until Tehran returns the “ransom money”  and instead settles claims from American victims of Iranian terrorism.

Democrats do not appear to be on board with either measure. There are no Democratic co-sponsors on the Rubio-Pompeo legislation, and a spokesman for House Foreign Affairs Committee Ranking Member Eliot Engel (D-N.Y.) said Tuesday afternoon that Democrats could not comment on legislation they were reviewing.

The payments to Iran were announced in January alongside the official implementation of the Iran nuclear deal. Republicans have strongly opposed the multilateral pact since it was struck last summer, though they were unsuccessful in blocking its implementation.

But the GOP has leapt on the $400 million payment as the latest objectionable piece of the Obama administration’s dealings with Iran.

GOP leaders in Congress and on the campaign trail first speculated that the settlement of Iran’s long-running claim for the  might be a “ransom” when the administration announced it on the same day as the release of American prisoners last January. Both things happened on the day of implementation of the Iran nuclear deal.

The settlement was intended to resolve a dispute before an international tribunal at The Hague over funds Iran paid decades ago to buy weapons from the United States, the sales of which was suspended after Iran’s 1979 revolution broke out.

When it emerged last month that the administration had delayed the $400 million cash payment to coincide with the date of the prisoners’ release, Republicans doubled down on their “ransom” charges.

Since the nuclear deal was announced, lawmakers have launched several attempts to push back against it — releasing legislation to sanction Iran over its ballistic missile tests, human rights abuses, and support for terrorism.

But Royce has been especially concerned with the matter of cash payments being made to Iran, warning last spring that “Iran’s supreme leader must not be allowed to seek ‘death to America’ with U.S. dollars in his pocket.”

His new bill seeks to ensure that the United States “may not provide, directly or indirectly,” any cash from the U.S. or a foreign government to Iran. It also requires the president to submit a report to Congress every six months detailing what claims before The Hague tribunal are outstanding, in what amounts, and when the administration expects they will be resolved.”

“The huge concern here is that it’s all about the cash,” a congressional aide said of Royce Tuesday. “It’s about the dollars.”

But Democrats say cash payments to Iran are necessary because sanctions have effectively cut Iran out of the international banking system, and thus should not cause so much concern.

“They can’t deal in banking, because banks won’t deal with Iran,” Sen. Ben Cardin (D-Md.), ranking member of the Senate Foreign Relations Committee, said Tuesday when asked if cash payments were a concern. “The fact that it’s in cash is somewhat not typical, and it does not look good, but my understanding is that Iran has not been able to establish banking, international banking and that’s part of our strategy. We don’t want to facilitate that.”