US House Speaker John Boehner says all options are on the table to prevent President Barack Obama from finalizing the Iran nuclear agreement, including the threat of using a lawsuit against him.

Boehner told reporters on Thursday during a news conference that legal action is “an option that’s very possible.”

“If you read the provisions in [the congressional review law], it’s pretty clear that the president has not complied,” the Republican said.

“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,” he stated.

He added that the Iran nuclear agreement is "worse than anything I could’ve ever imagined."

Earlier this year, Boehner invited Benjamin Netanyahu to address a joint session of the US Congress, where the Israeli premier ranted for nearly 40 minutes against the Iran nuclear talks, warning Washington that it was negotiating a “bad deal” with the Islamic Republic.

The invitation to Netanyahu was extended without consultation with the White House, drawing angry reaction from the Obama administration, which called it a breach of protocol.

Boehner has been a staunch opponent of the Iran nuclear agreement. He made the remarks as the Senate is gearing up for a key procedural vote on a Republican resolution disapproving of the Joint Comprehensive Plan of Action (JCPOA).

However, Senate Republicans have conceded that the Obama administration has prevailed and the July 14 Vienna accord could not be stopped now.

Obama has secured enough Senate support to block the vote on the Iran agreement even without issuing a veto as four more undecided Democratic senators came out in support of the deal.

The announcement on Tuesday by Senators Richard Blumenthal of Connecticut, Ron Wyden of Oregon, Gary Peters of Michigan and Maria Cantwell of Washington brought the total number of senators who back the agreement to 42.

The level of support would potentially block passage of the resolution by paving the way for a filibuster of Republican attempts to disapprove of the nuclear agreement.