Sen. Bill Cassidy (R-La.) reportedly yelled at Donald Trump during a closed-door lunch with members of the Republican Senate conference on Wednesday.

According to reports, Cassidy, who lost his primary to a Trump-backed candidate, confronted Trump over the recently signed memorandum of understanding with Iran.

“Cassidy was ‘yelling’ at Trump, the source said. This source also tells me that Trump went after Sen. Dave McCormick (R-Pa.) for missing yesterday’s war powers vote, which was successful, 48-50. But worth noting: McCormick was with Trump at a Pennsylvania rally. And even if he were at the Capitol, the resolution still would’ve been successful because McConnell was absent,” MS NOW congressional correspondent Mychael Schnell wrote in a post on Twitter.

Trump also slammed Sens. Rand Paul (R-KY), Susan Collins (R-ME), and Lisa Murkowski (R-AK), who joined Cassidy in voting to rein in Trump’s Iran war powers.

“Cassidy came in guns blazing, at one point stopped calling Trump ‘Mr. President’ and referred to him as ‘brother.’ Trump repeated what he’s said on social media about the housing bill, SAVE Act & the filibuster, but nobody pushed back,” PunchBowl News reported.

The meeting came hours after Trump vowed not to sign into law a bipartisan affordable housing bill without progress on his SAVE America Act, a voting bill pushed by Trump and his allies which would disenfranchise millions of voters.

Though a source in the meeting told Semafor congressional bureau chief Burgess Everett it is “a total cluster f—,” Trump emerged from the closed-door lunch claiming that Republicans are united.

Cassidy later admitted to yelling at Trump, telling reporters, “I stood and said, ‘You have not told the American people what’s going on. It’s lasted four months. Our original objectives have not been achieved, and I want to know what’s going on.”

Trump “did not particularly care for my comments, raised his voice, I lost my temper…it’s the Irish in me,” the senator added.

“But again I matched his tone and his volume, and it went back and forth… so I sat down and tried to de-escalate, I guess my point is, though, that the American people need to know more than we are being told. The Senate needs to know,” he concluded.

Cassidy has been vocal in opposing the MOU signed between the Trump administration and Iran.

He called the deal “a tremendous foreign policy blunder,” and said it “will only end up making Iran “stronger” and U.S. allies in the region “end up weaker.”