Four Louisiana congressmen joined forces with hundreds of other House representatives to issue a warning to President Obama.
The Republican representatives sent the president a letter pointing to what they call "grave and urgent issues that have arisen" surrounding nuclear negotiations with Iran.
The letter insists any nuclear deal will require Congressional approval. A group of Republican senators sent a similar letter to Iranian leaders.
"Do we really negotiate in an honest and forward way with individuals like this?" asked North Carolina Republican Sen. Richard Burr on FOX News. "The administration has consistently done it for two-and-a-half years and ignored what Congress thought, ignored Congress from the standpoint of updates. They should've expected Congress, at some point, would be very vocal. I think that's what you are seeing."
Louisiana representatives Scalise, Boustany, Fleming and Graves signed the letter.
House Democrats call the letter meddling.