WASHINGTON — The UN Security Council is set to vote Monday on a resolution backing the new Iran nuclear deal in a move that has Republican and Democratic senators fuming about an end-run around Congress.

Senate Foreign Relations Committee chairman Bob Corker (R-Tenn.) blasted the move as “an affront to the American people. I look at that as an affront to Congress and the House of Representatives.”

Sen. Ben Cardin of Maryland, the senior Democrat on the panel, said he also was distressed.

“If the United States is signing onto the United Nations program and later on we’re not part of it, what we’ll do is inconsistent with the UN resolution,” Cardin noted.

Obama administration negotiator Wendy Sherman said it would have been “difficult” to change the timing of the vote because nations who partnered with the US wanted to go to the UN first.

“Since it is a product of the United Nations process, for us to say, ‘Well, excuse me, the world, you should wait for the United States Congress,’ [was impractical],” she said.