As the partial federal shutdown slips into its 35th day, cracks are beginning to appear in the Republican Party’s resolve to support President Donald Trump’s demands for a southern border wall.

Every day that passes without a solution puts more pressure on lawmakers to reopen the government. The situation is particularly pressing for Republicans, as the president allowed—and even said he would own—the closure in the hope of winning funding for his contentious wall.

The tension boiled over into ill-tempered sniping at a private Republican luncheon on Thursday, The Washington Post reported, as senators rounded on Vice President Mike Pence and Majority Leader Mitch McConnell, both of whom are consistently supportive of Trump’s divisive strategy.

Citing two Republicans who attended the event, the Post reported that Wisconsin Senator Ron Johnson was among the lawmakers expressing their anger, turning on McConnell and declaring, “This is your fault.”

McConnell reportedly replied, “Are you suggesting I’m enjoying this?” The testy exchange was later confirmed by Ben Voelkel, a spokesperson for Johnson. He said the senator was expressing his frustration over defeated efforts to reach a deal on reopening the government.

One Republican and one Democrat funding plan failed in the Senate on Thursday, though neither was expected to succeed. The Republican bill proposed $5.7 billion in funding for Trump’s wall, with legal protections for some immigrants added to sweeten the deal for the opposition. The Democrat plan would have provided funding for the government to reopen until February 8 but no funding for the wall.

Senator Mitt Romney of Utah spoke during the lunch to explain why he planned to vote for both the Republican and Democrat funding bills. When interrupted by North Carolina Senator Thom Tillis, Romney reportedly snapped at his colleague. The Post reported that the exchange was lively but not angry, citing one person who was in attendance and another who was familiar with the conversation.

Lawmakers on both sides of the aisle are facing pressure from constituents to reach an agreement to end the longest government shutdown in U.S. history. Hundreds of thousands of federal workers will miss their second consecutive paycheck on Friday, with no end to their misery in sight.

McConnell has been criticized for his refusal to allow any House-approved proposals to be tabled for a Senate vote, maintaining he would not consider any legislation that would be vetoed by the president. Thursday’s votes were the first in the Senate since the shutdown began on December 22, 2018. McConnell has so far blocked four House-approved funding proposals from being heard in the Senate.

Republican intransigence is starting to bite, even though Trump and his allies have sought to shift the blame onto what the president called “obstructionist” and “radicalized” Democrats. Polls indicate that most Americans blame Trump and his party for the crisis.

Senators voiced their concerns to Pence during Thursday’s lunch event. Even McConnell was believed to have addressed the vice president directly, saying the shutdown was not his idea and was not working. Republicans familiar with his comments said he used the phrase “There is no education in the second kick of a mule” in discussing the government shutdown.

According to The Hill, another Republican senator told Pence, “The shutdown needs to come to an end; this is not a strategy that works, [and] we never should have had a shutdown in the first place.”

An anonymous source told the website that the vice president reportedly explained, “The president is interested in striking a deal.”

Texas Senator John Cornyn, speaking with reporters after the lunch, claimed that no lawmakers were “blaming the president,” the Post reported. However, he said, “There was a lot of frustration expressed about the situation we find ourselves in.”

This article has been updated to include comments made by Senator John Cornyn.