(CNN) — Congress remained on track Friday to trigger a government shutdown, as House Speaker Kevin McCarthy suffered another high-profile defeat when the chamber failed to advance a last-ditch stopgap bill to extend government funding past a critical deadline.

• From News 8: All seven Indiana House GOP members voted for the measure. A total of 21 GOP House members voted “no.”

McCarthy is under intense pressure as House Republicans have not been able to coalesce around a plan to prevent a shutdown amid hardline conservatives’ resistance to passage of a short-term funding extension.

In the aftermath of the failed vote, McCarthy argued that aid to Ukraine should be dropped from a bipartisan stopgap bill in the Senate – though, given how little time remains, it is not clear that any kind of deal could be reached prior to a shutdown taking effect Saturday at midnight.

“I think if we had a clean one without Ukraine on it, we could probably be able to move that through. I think if the Senate puts Ukraine on there and focuses on Ukraine over America, I think that could cause real problems,” he told CNN’s Manu Raju.

McCarthy said he had proposed putting up a “clean” stopgap bill and that he was “working through maybe to be able to do that.”

“We’re continuing to work through – trying to find the way out of this,” the California Republican said.

A number of House Republicans oppose additional funding for war-torn Ukraine, which is included in the Senate’s stopgap bill that would keep the government funded through Nov. 17.

Twenty-one Republicans crossed over to vote with every Democrat against the House stopgap bill on Friday in a 232-198 vote. The measure – a 30-day extension that would slash funding from current levels – also includes strict GOP-led border policies. House GOP leadership hoped that border security provisions tucked into the temporary measure would force hardliners’ hands – but it was not enough.

McCarthy and his leadership team now plan to see if there is any willingness among the 21 holdouts to accept a short-term spending bill to keep the government open for a couple of weeks. If there is, then that plan could come to the floor. Otherwise, they may be forced to accept the Senate bill with no hand to play.

McCarthy is now confronting the most significant challenge to his leadership to date as he faces pushback from hardline conservatives and threats over the possibility of a vote to oust him as speaker.

After the House failed to pass the stopgap bill, McCarthy told Republicans at a closed-door conference meeting there aren’t many options to avoid a shutdown, according to sources in room.

He told his members they can either approve the GOP’s stopgap plan that failed, accept a Senate proposal, put a “clean” stopgap on the floor to dare Democrats to block it – or shut down the government. A large number of House Republicans have already vocally criticized the Senate proposal, making that unlikely to pass in the chamber.

During the closed-door conference meeting, House GOP leadership also proposed that members stay in session the next two weeks to vote on more individual appropriations bills, according to multiple lawmakers in the room.

That plan would not help avert a government shutdown this weekend, but Republicans are hoping that leadership’s proposed schedule change might convince some holdouts to support a short-term funding option in the meantime.

GOP Rep. Ken Buck, who voted against the House GOP stopgap funding measure Friday, said the failed effort was a “no confidence vote” in McCarthy.

“This was a vote where people didn’t have faith that Kevin McCarthy was going to do the right thing. We passed a vote on the debt ceiling. He went and negotiated a significantly higher number with President Biden. People don’t have faith that when it comes time to negotiate he’s going to do the right thing,” Buck told CNN’s Jake Tapper on “The Lead.”

On Thursday, the speaker refused to say whether he would try to cut a deal with Democrats – a step that could prompt conservatives to move to oust him from the speakership.

“I still got time, I got time to do other things,” McCarthy responded when asked by CNN what will happen if the stopgap bill fails.

Pressed further on whether he has a Plan B, McCarthy said, “In this job you got to have an ABCDEF and G,” and he laughed when asked what letter he was currently on. “I haven’t spelled my name out completely,” he responded.

A shutdown could have enormous impacts across the country, in consequential areas ranging from air travel to clean drinking water, as many government operations would come to a halt, while services deemed “essential” would continue.

House GOP leaders brought a series of spending bills to the floor Thursday evening as they try to show conservatives they are working in good faith to advance full-year funding bills.

The House passed several of those spending bills, but the measures would not stop a shutdown and have no hope of passing in the Senate.

At the end of the night, a bill to fund the Department of Agriculture failed to pass on the floor with 27 Republicans voting against it, highlighting once again the difficulty Republicans have had coalescing around spending bills.

Meanwhile, the Senate is working to advance a bipartisan stopgap bill that would keep the government open through Nov. 17 and provide additional aid to Ukraine and disaster relief. McCarthy has so far dismissed that bill.

It could take until Monday to pass the Senate’s bill to keep the government open if GOP Sen. Rand Paul slows down the process – as he has vowed to do – over his demand that the bill drop the $6.2 billion in aid to Ukraine it contains, according to senators. That would put it past the Saturday evening shutdown deadline.