Republican Congresswoman Marjorie Taylor Greene has launched a bid to oust Speaker of the House Mike Johnson, the latest move in a long-running internal party battle.
As the House of Representatives was voting to approve a $1.2tn (£950bn) spending package that would avert a partial government shutdown at midnight, the Georgia Republican filed a "motion to vacate".
If she takes the next step and formally introduces the measure, the House could vote on Mr Johnson's fate within days.
Ms Greene, a strong supporter of Donald Trump, said she was starting the removal process as "more of a warning".
The Louisiana congressman won the speaker's job last October after the previous Speaker, California Congressman Kevin McCarthy, was ousted through a similar tactic.
There were weeks of acrimony before he took up the gavel, as several more prominent Republicans tried and failed to secure enough support to win a majority in the chamber.
On Friday, more than 100 Republicans voted against the spending bill backed by Mr Johnson and other Republican leaders.
A group of hard-line conservatives, including Ms Greene, objected to the amount of funding authorised, a lack of sweeping changes to US immigration policy and several provisions supporting healthcare clinics that perform abortions.
Ms Greene, speaking on the steps of the US Capitol after the spending vote, said that Mr Johnson had "betrayed" Republicans.
She said she did not want to throw the House into chaos, but that she would move forward with her motion to vacate if House Republicans did not find a new leader.
"I have respect for him as a person, but he is not doing the job," Ms Greene said.
At the moment, however, the Georgia Republican appears to have little support within her own party for the move.
Florida Republican Matt Gaetz, who led the push to oust Mr McCarthy, said that this latest effort could ultimately lead to a Democratic speaker, perhaps with the backing of centrist Republicans.
Speaking to reporters at the Capitol, Republican Congressman Mike Lawler called the move "idiotic" and said it harmed conservative priorities and the nation as a whole.
On Friday afternoon, the narrow Republican majority in Congress dwindled even further, as Wisconsin Congressman Mike Gallagher - who had already announced he was not running for re-election - said he would formally resign from his seat on 19 April.
At that point, Ms Greene would only need one Republican to join her in voting Mr Johnson out, assuming no absences and all the Democrats agree to cooperate.
That last bit may not be guaranteed, however.
Some Democrats have expressed reluctance to help trigger another House power struggle. If Ms Greene is only able to convince a handful of Republicans to go along with ousting Mr Johnson, it would require near unanimous Democratic approval for that vote to pass.
Democrats provided that support last year to oust Mr McCarthy, who many had viewed as operating in bad faith. Mr Johnson, who negotiated with Democrats to craft Friday's government spending package, has not engendered such ill will.
