South Carolina Sen. Lindsey Graham is throwing down the gauntlet, warning the White House he’ll move to cut funding to the United Nations if the administration turns to the international body to lift sanctions on Iran as part of a nuclear deal.

Graham made the comments Thursday during an appearance on Fox News’ “On the Record With Greta Van Susteren.”

Graham, a Republican, is chairman of the Senate Appropriations Committee’s Subcommittee on State, Foreign Operations and Related Programs. In that role, he says he can block U.S. funding for the United Nations -- $654 million is earmarked for 2015 alone. 

“Twenty-two percent of the funding for the United Nations comes from the American taxpayers, and I’m in charge of that account,” a defiant Graham told Fox News. He acknowledged he'd also need other lawmakers to sign onto any effort to suspend that funding. 

Graham is worried that the administration, should it strike a nuclear deal with Iran, might get the U.N. to lift sanctions without going through Congress to lift U.S. sanctions. 

Graham, who says the worst possible outcome would be for Iran to get a nuclear weapon, vowed:  “I’m not going to allow the United Nations to be used as a way to get around the United States Congress for a deal that affects the very existence of Israel and our own national security.”

When pushed on the issue, Graham said, “If they go to the U.N. Security Council, and the U.N. Security Council lifts all sanctions before we ever get a chance to look at this deal, absolutely I would suspend funding the United Nations, because I don't think your money should go to an organization that irresponsible.”

Graham strongly admonished the Obama administration.

“They are about to make a mistake for the ages,” Graham said. Earlier this month, Graham made a similar threat during a speech he gave at the American Israel Public Affairs Committee. At that event, he said he’d slash U.N. funds if the U.N. marginalized Israel. 

International nuclear talks with Iran are expected to resume next week, following some disagreements -- reportedly over the sanctions issue -- on Friday. 

Asked about the talks on Friday, White House Press Secretary Josh Earnest said he did not want to speculate on what an actual deal might look like. But he said President Obama does not believe it makes sense to remove "a large number of sanctions at the front end of this agreement" -- as the Iranians reportedly want. 

Earnest stressed the importance of existing congressional sanctions. But he indicated the administration, should there be a deal, might be able to waive them down the road. "One of the most powerful tools that we have in these negotiations are the congressional sanctions that Congress has passed, that those are some of the toughest sanctions that have ever been put in place against any country by the United States," he said. "And the president believes that we should leave those sanctions in place for -- not just for a few weeks to verify Iranian compliance."

He added: "He believes that we should leave those sanctions in place over the longer term, and that the president can use the waiver authority that Congress has already given him, to relax some of those sanctions."