US House Speaker John Boehner is threatening to sue President Barack Obama because of the secret agreements over the Iran nuclear deal, whose approval is still pending in the US Congress.

The Republican House leader accused the president of failing to disclose details of the agreement to Congress as required by law and, because of this, a lawsuit is "an option that is very possible."

"If you read the provisions in [the congressional review law], it's pretty clear that the president has not complied," Boehner said, according to Charisma News. "Because it makes clear that any side agreements and any other type of an agreement—including those that do not directly involve us—must be turned over as part of it. I do not believe that he's complied."

It was reported last month that "an unusual secret agreement with a UN agency will allow Iran to use its own experts to inspect a site allegedly used to develop nuclear arms."

Obama and Secretary of State John Kerry have not seen the text of the agreement, the report said.

Republicans said the secret agreement violates the Iran Nuclear Agreement Review Act, passed in the spring and required Obama to turn over all documents associated with the deal to Congress.

Communications Director Dan Holler of Heritage Action said the process under the review act has been a "complete failure" to allow Congress to "reassert" its constitutional authority.

"The House's refusal to go along with that process is encouraging, though lawmakers will need to do more if they want to rein in this administration," he said.

Boehner described the deal as "worse than anything I could've ever imagined."

"This debate is far from over and, frankly, it's just beginning," he said. "We will use every tool at our disposal to stop, slow and delay this agreement from being fully implemented."

The House is set to vote this week on a bill that condemns President Obama for not transmitting the side agreements to the US Congress.

Congress has until Sept. 17 to vote on the deal before it is implemented.

White House spokesman Josh Earnest brushed aside Boehner's threat, saying, "We obviously feel quite confident in our ability to move forward with the rest of the international community."