House Speaker Kevin McCarthy privately delivered a message to Senate GOP Leader Mitch McConnell this week: The Senate's bipartisan bill to keep the government open wouldn't get a vote in his chamber unless significant changes are made.

And then when the speaker appeared before his conference on Wednesday morning, McCarthy relayed that same message and later made clear he wouldn't put the Senate bill on the House floor, underscoring the divide between the two most powerful Republicans in Washington at a pivotal moment for the country and their party.

With just days left until government funding runs dry, the two men are at sharp odds as McCarthy is rejecting the deal McConnell cut with Senate Majority Leader Chuck Schumer and still trying to rely on House GOP votes to bolster his conference's negotiating position.

A number of Senate Republicans and Democrats alike are alarmed that McCarthy is pushing a plan that appears unlikely to pass his own chamber -- and has no chance of becoming law -- as top GOP lawmakers fear that the divisions within their own party would make it easier for the public to blame them for a damaging impasse.

"This is completely avoidable," said Sen. John Cornyn, a Texas Republican and close McConnell ally. "And I think really represents a failure of governance."

McCarthy and his allies believe that the Senate deal is lackluster since it's silent on funding for border security, a chief demand for the House GOP. And McConnell, a champion of Ukraine in its war against Russia, pushed to include $6 billion in aid, even though McCarthy had said for weeks that that the stop-gap measure should punt on the issue amid outcries from his conference.

"If you were to look at the four corners, I think that you've got McConnell closer to Schumer and Hakeem (Jeffries) than he is the speaker," Rep. Cory Mills, a Florida Republican, told CNN. "The speaker is kind of out there on his own, in all honesty. It's a one-three vote at all times."

In the private phone call, McCarthy explained to McConnell that House Republicans couldn't get behind any spending measure that doesn't significantly address the US southern border while also including aid to Ukraine.

"They're working as a uniparty up there," said GOP Rep. Max Miller of Ohio, referring to Republicans and Democrats in the Senate.

The divide is just the latest example of how McCarthy and McConnell have splintered over tactics, including as of late with McConnell uneasy about the push toward a potential impeachment of President Joe Biden and as he's eager to move away from former President Donald Trump -- all as McCarthy green-lit a Biden impeachment inquiry and has embraced former President Donald Trump. Their split was also on full display last week when McConnell and Schumer publicly appeared together with Ukrainian President Volodymyr Zelensky in the Capitol, while McCarthy opted not to.

In recent weeks, Senate GOP lawmakers have been critical of McCarthy's decision to ignore a bipartisan debt ceiling law the speaker cut this summer that set spending levels for the government. The goal of that deal was to avoid a messy spending fight in the fall.

But under pressure from his right flank, which held the House floor hostage, McCarthy agreed to seek deeper cuts, putting him on a collision course with Republicans and Democrats alike in the Senate who are opposed to that effort.

"If you make a deal, you've got to stick to the deal," Sen. Shelley Moore Capito of West Virginia, a member of Senate GOP leadership, told CNN. But she added: "I understand that the speaker has a lot of pressures on him, so I don't want to judge why he's doing what he's doing."

Capito also pushed back on House Republicans' rejection of the Senate's short-term spending bill that was brokered by McConnell and Schumer. "I think one thing we know about the House is they're kind of unpredictable right now," she said. "I served in the House, there is always that natural rivalry, but I think we have to get to an end."

Allies close to McCarthy and McConnell insist the pair have a good working relationship and that McCarthy's phone call was not contentious and more of a courtesy, noting they communicate and meet regularly when the chambers are in session. More importantly, allies say, each man has an understanding -- and respect for -- the position the other one is in, even if those positions are sometimes in conflict with one another.

Speaking to reporters, McCarthy pinned the blame on Schumer -- not McConnell.

"Mitch is not in the majority over there," McCarthy said. "He's got to work with Sen. Schumer."

McConnell pointed to the institutional differences between the two bodies, saying they're "quite different," even as he defended the Senate's plan.

"I'm comfortable with the way we put together the Senate bill," McConnell said.

Still, as each chamber pursues its own plan to avoid a shutdown, there couldn't be more daylight between the two men. Unlike when McConnell stayed on the sidelines during the debt ceiling fight and was content to let McCarthy take the reins, the Senate GOP leader worked with Schumer to negotiate a stopgap bill to extend current funding levels for 45 days.

The proposal, which advanced with overwhelming bipartisan support on Tuesday, also includes an additional $6 billion for disaster relief and $6 billion for Ukraine, which has been a top priority for McConnell.

By contrast, McCarthy has been trying to round up House Republican votes for a partisan funding plan that would extend current spending at lower levels, includes no money for Ukraine or disaster, and adds a House GOP border security package. But it's still unclear whether McCarthy will even have the votes to muscle the measure over the finish line, given hardliners are still digging in. Failure to pass his own bill would undermine McCarthy's negotiating hand with the Senate -- especially with McConnell and him already on different pages about the path forward.

"I don't see the support in the House," McCarthy told reporters, referring to the bipartisan stopgap bill.

But at least some GOP senators are expressing support for McCarthy's position. On Tuesday, Sen. Kevin Cramer, a North Dakota Republican, was walking through the House side of the Capitol when he bumped into the speaker, and pulled him aside for a brief conversation.

Cramer, a McConnell ally, is personally supportive of Ukraine aid but said he told McCarthy he agreed it was a bad idea to put any Ukraine aid in a stopgap bill, knowing it would likely be rejected by House Republicans.

"I said, 'I want to send over whatever's most helpful to getting it done over here, and I don't think Ukraine funding does that,'" Cramer said.