House Republican leaders wrote to President Joe Biden on Monday accusing the administration of reaching a secret nuclear “understanding” with Iran in violation of U.S. law and threatening to “use all tools at our disposal” to impose a maximum pressure policy toward Iran.

House Majority Leader Steve Scalise (R-LA), Republican Conference Chair Elise Stefanik (R-NY) and House Foreign Affairs Committee Chair Michael McCaul (R-TX) penned a letter expressing “significant concern that your Administration is pursuing a nuclear understanding with Iran alongside a hostage release deal.” 

They said that recent steps by Iran to slow enrichment and dilute some of its stockpiled uranium indicate that the administration had secured an “understanding” on Iran’s nuclear program “inextricably linked” to the recent deal to release U.S. hostages in exchange for $6 billion in frozen Iranian funds. The lawmakers said such a deal would be “a clear violation” of the Iran Nuclear Agreement Review Act, which provides for congressional review of any agreement pertaining to Iran’s nuclear program.

“Our citizens deserve answers about why your Administration is rewarding an Iranian regime that is targeting Americans overseas and at home,” the lawmakers wrote. “Should the Administration continue to ignore U.S. law and flout congressional oversight, we will use all the tools at our disposal to bring transparency and accountability to the American people and return to a policy of maximum pressure.”

Scalise, Stefanik and McCaul added that, without fully ending Iran’s nuclear enrichment, any deal would only be “entrenching” Iran’s nuclear program, and that slowing the pace of its stockpiling “does not significantly change [the] threat” the program poses.

The lawmakers also slammed the hostage deal, which included the release of $6 billion in frozen Iranian assets, as creating a “direct incentive for future hostage-taking by U.S. adversaries” and said it would only prompt Iran to demand more for other hostages going forward. They added that the released funds could support Iranian malign activities, and noted that other U.S. non-citizen permanent residents would remain imprisoned in Iran under the agreement.

“Assurances that the money will be limited to humanitarian goods are insufficient because money is fungible,” the GOP leaders argued. “Regardless of restrictions, this deal frees up $6 billion in funds for the regime to finance its military program, terrorist proxies, nuclear activities, and repression. Iran has also previously lied about such humanitarian transactions.”

Separately, McCaul and Rep. Brian Mast (R-FL), who chairs HFAC’s Subcommittee on Oversight and Accountability, wrote to Secretary of State Tony Blinken pressing for more information on the status of Special Envoy for Iran Rob Malley. Malley is reportedly under investigation by the FBI for alleged mishandling of classified information; his security clearance has been suspended and he is on leave from the State Department.

McCaul and Mast wrote that they see the recent announcements that Malley will be taking up posts at Princeton and Yale Universities as a sign of “a change to his employment status and that he will be leaving the State Department.”

The lawmakers said they were “not satisfied” with the responses they received last month at a classified briefing about Malley by State Department officials, and said they are “concerned that some officials at the Department, including yourself, knew about Mr. Malley’s situation for months but did not communicate to Congress about it.”

The lawmakers requested to be kept up to date on Malley’s status.