The top Republican and Democrat on the Senate Foreign Relations Committee emerged from a meeting with Vice President Joe Biden on Thursday to say they oppose President Obama's plan to seek approval of his Iran agreement at the United Nations before Congress can weigh in.

Biden met with Senate Democrats on the committee he used to lead to answer questions about the deal, but clashed with senators over the plan to get the U.N. to approve the deal first. The U.N. will begin considering the agreement Tuesday, just one week after the U.S., Iran and other world powers finalized the deal and announced it.

"We have a great concern with that," said Sen. Bob Corker, a Tennessee Republican who chairs the committee. "I think it's an affront to the American people … what this means is that they are agreeing to an agreement they don't even know if they can implement."

Corker showed up to the meeting at the tail-end but did not participate in an extended back and forth with Biden, according to knowledgeable aides.

"I question the judgment of our president and the other members" involved in the negotiations in presenting this to the United Nations for approval when the American people haven't had a chance to take a hard look at its details and see what their members of Congress think about it, he told reporters after meeting with Biden.

The statement was particularly bold coming from Corker, who has tried to walk a fine line between allowing the Iran negotiations to continue before Congress moved to issue more sanctions and remaining skeptical of the deal's detail.

Sen. Ben Cardin, a Maryland Democrat and the ranking member of the panel, also said Congress should act first.

"I think that the administration should wait until Congress has its review process," he said. "That issue did come up and we got into some of the historic differences between the executive and the legislative branches. Vice President Biden said it's not unusual for the administration to have different views on that than Congress."

Overall, however, Cardin said the discussion was very "helpful," "comprehensive" and "open and direct," covering the deal's inspections process and different enforcement mechanisms and the views of U.S. allies in the region. Biden, he said, has a "really great rapport with our committee having been a former member of our committee."

While Corker was speaking to the press, Biden left via a back stairwell without addressing the media or making any comments.

Other senators leaving the meeting were tight-lipped about Biden's talk, and most declined to comment.

"The vice president is a very compelling advocate as someone who is one of the most seasoned and senior participants — leaders — in American foreign policy and national security over decades," said Sen. Christopher Coons, D-Del. "He answered a whole series of difficult, demanding questions and provided encouraging and thoughtful response."

Coons begged off when reporters asked him if the vice president persuaded him on any key points.