A far-right Republican lawmaker launched a bid on Monday to oust US House Speaker Kevin McCarthy from his post, reigniting an intra-party battle between traditional conservatives and firebrand supporters of ex-president Donald Trump.
Matt Gaetz, a representative from Florida, entered his resolution from the House floor "declaring the office of Speaker of the House of Representatives to be vacant."
The resolution, which requires a majority to pass, will not be voted on immediately.
Gaetz is a leading figure within the small group of far-right Republican legislators who brought the government to the brink of shutdown with their refusal to adopt fresh federal funding without deep spending cuts.
The group also opposes sending additional support to Ukraine, saying the money would be better spent in the United States on combatting illegal immigration.
The hardliners hold a de facto veto over legislation in the House, given Republicans' narrow victory in the midterm elections last November.
After the chamber passed a last-minute measure on Saturday to extend funding -- at current levels and without new Ukraine aid -- Gaetz said he would move to oust McCarthy.
"I think we need to rip off the Band-Aid," Gaetz told CNN on Sunday.
In order to gain the speaker's gavel in January, McCarthy was forced to make concessions to the far-right bloc, including a rule change that allows one member to file a such a "motion to vacate."
The timeline for next steps on Gaetz's resolution is variable, and it is not yet clear if Democrats would come to McCarthy's aid.
Gaetz said on Sunday he believed he had enough Republican support to oust McCarthy.
"The only way Kevin McCarthy is speaker of the House at the end of this coming week is if Democrats bail him out," Gaetz told CNN.
US President Joe Biden has lambasted both McCarthy and the hardliners for failing to live up to an agreement forged around a debt crisis months ago that was meant to avoid a damaging shutdown fight -- and for stripping out support for Ukraine.