Sen. John Thune, R-S.D., shot down President Trump on Sunday, saying deploying the "nuclear option" in the U.S. Senate would fundamentally alter the way the upper chamber conducts parliamentary business.

"I know the president is anxious, he's frustrated. We are as well. Going to 51 on legislation is something that has been talked about before, but it would fundamentally change and transform the way the Senate functions," Thune told Fox News.

"And I think that we ought to be able to solve this without taking that extreme measure," the Republican Conference chairman continued, referring to the partial federal government shutdown.

Earlier Sunday, Trump tweeted his endorsement of GOP members going "nuclear" to pass a long-term budget with a simple majority in the Senate if the government remained closed for too long.

White House budget director Mick Mulvaney backed up the president's calls, but said he would prefer for Senate Democrats to get on board with a continuing resolution to reopen the government.

But Thune voiced his opposition to amending the 60-vote threshold rule to end debate on policy bills.

"We ought to be able to get 60 votes, Republicans and Democrats, who agree to keep the government open and functioning so we can negotiate these other important issues that the American people expect us to deal with," he said. "I don't think there's a need to go to 51."