Frustrated GOP senators read Vice President Pence the riot act at a closed-door meeting Thursday, telling him the partial government shutdown needs to end soon, according to lawmakers in the room.

Republican senators, including Senate Majority Leader Mitch McConnell (Ky.), warned the vice president that prolonging the shutdown is not a smart political strategy, in hopes of sending a clear message to President Trump that he needs to resolve the crisis as soon as possible.

Lawmakers vented their irritation to Pence shortly before six GOP senators defected to vote for a Democratic-backed bill that would open the government without funding Trump's proposed border wall.

One GOP senator said lawmakers 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."

Pence in turn told them that "the president is interested in striking a deal," according to the source.

The pushback against Pence came from outspoken critics of the shutdown like Sen. Lisa Murkowski (Alaska), as well as from lawmakers who usually keep a lower profile - Sens. John Boozman (Ark.), Johnny Isakson (Ga.) and Jerry Moran (Kan.).

One of the most remarkable moments during the Senate luncheon came when McConnell told Pence that shuttering the government to try to secure funding for a border wall was not a smart approach.

"McConnell talked about how we need to bring this process to a close; we should never have had a shutdown; they don't work; I've said this numerous times; I don't know how many times I've told you there's no education in the second kick of a mule," said a GOP source familiar with the meeting.

A spokesman for McConnell declined to comment on specific conversations during the private lunch but noted that the Kentucky Republican made his thoughts about a potential government shutdown clear in mid-December.

"I think that a government shutdown is not a good option. That's my view. The American people don't like it," the GOP leader told reporters on Dec. 18, four days before funding lapsed. "You remember my favorite country saying, 'There's no education in the second kick of a mule.' We've been down this path before."

Sen. Bill Cassidy (R-La.) said after Thursday's meeting but before the Senate votes that colleagues were "airing their concerns."

Sen. John Cornyn (R-Texas) told reporters after the Senate votes that Pence got an "earful" from senators.

"We're all hearing from our constituents who are working for no pay," Cornyn said. "And there's a parade of horribles of how people who are having to cope with not getting paid, and it's not good."

"There was a lot of frustration expressed about the situation we find ourselves in," he added.

Pence urged Republican lawmakers at the lunch to stay unified, pressing them not to vote for the proposal from Senate Democratic Leader Charles Schumer (N.Y.) to fund the government until Feb. 8 without additional funding for a border wall, according to the GOP source familiar with the meeting.

To underscore the stern message they sent to Pence, six Republicans - Murkowski, Isakson and Sens. Lamar Alexander (Tenn.), Susan Collins (Maine), Cory Gardner (Colo.) and Mitt Romney (Utah) - voted for the Democratic proposal. But the 52-44 vote fell short of the 60 needed to advance the bill.

Murkowski said after the votes that she told Pence the shutdown has to end as quickly as possible.

"I reminded colleagues that I was feeling a very keen sense of urgency on this because Alaska has the highest number of federal workers that are impacted by the partial shutdown and we needed to get this open now," said Murkowski, who is supporting a measure with Democratic Sens. Ben Cardin (Md.) and Chris Van Hollen (Md.) that would reopen the government for three weeks without providing wall funding.

Isakson's spokeswoman, Amanda Maddox, said her boss "spoke to his colleagues at today's lunch to share his reasoning for voting the way he planned."

"He didn't know the vice president would be at today's lunch when he decided on making the speech," Maddox said. "He wasn't trying to send any message but was merely speaking his conscience."