The White House has confirmed that any nuclear agreement between Iran and the P5+1 group of world powers would be subject to a vote by the UN Security Council.

The acknowledgement by President Barack Obama's chief of staff Denis McDonough comes as the White House butts heads with Republicans over whether the US Congress should vote on any deal.

"Just as it is true that only Congress can terminate US statutory sanctions on Iran, only the Security Council can terminate the Security Council's sanctions on Iran," McDonough said in a letter on Saturday to Bob Corker, the Republican head of the Senate Foreign Relations Committee.

"Because the principal negotiators of an arrangement with Iran are the five permanent members of the Security Council, we anticipate that the Security Council would pass a resolution to register its support for any deal and increase its international legitimacy," he said.

On Friday, the State Department's spokeswoman Jennifer Psaki also said there would be an "endorsement vote" by the UN Security Council soon after an agreement is reached with Iran.

This would be separate from a resolution on lifting sanctions imposed by the United Nations on Tehran, she said.

That vote would occur later in a manner and date yet to be established, according to Psaki.

The Obama administration has been trying to dissuade lawmakers from passing a law, called Corker-Menendez, that would force the president to submit any agreement with Iran to Congress for approval.

Under the measure, Congress would have 60 days to review and possibly vote to block any agreement's entry into force.

"On this issue where Congress has played such a vital role, I believe it is very important that Congress appropriately weigh in before any final agreement is implemented," Corker said.

The Republicans are trying to assemble a two-thirds majority in both houses of Congress to pass the measure and override an Obama veto.

"Apparently the administration is on the cusp of entering into a very bad deal with one of the worst regimes in the world that would allow them to continue to have their nuclear infrastructure. We're alarmed about it," said Senate Majority Leader Mitch McConnell Sunday on CNN's "State of the Union."

"We will either be voting on a bill that would require the deal to come to Congress. The president said he would veto that. Or if there is no deal, we'll be voting on a bill that says the sanctions need to be ratcheted up," he said.