A far-right Republican congressman launched a bid on Monday to oust US House Speaker Kevin McCarthy, reigniting an intraparty battle between traditional conservatives and firebrand supporters of former president Donald Trump.
Matt Gaetz, from Florida, entered his resolution from the House floor “declaring the office of Speaker of the House of Representatives to be vacant”.
Mr Gaetz is a leading figure in the small group of far-right Republican legislators who brought the government to the brink of shutdown with their refusal to adopt new federal funding without deep spending cuts.
The group also opposes sending more support to Ukraine, saying the money would be better spent in the US battling illegal immigration.
The hardliners hold a de facto veto over legislation in the House, given the 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 – Mr Gaetz said he would move to oust Mr McCarthy.
To gain the speaker's gavel in January, Mr McCarthy was forced to make concessions to the far-right bloc.
The timeline for next steps on Mr Gaetz's resolution is variable, and it is not yet clear if Democrats would come to Mr McCarthy's aid.
The resolution requires a majority to pass. Mr McCarthy must call a vote within two legislative days, Bloomberg reported.
The move, officially called a motion to vacate the chair, is a parliamentary process that has not resulted in a speaker removal vote since 1910. In that case, then-speaker Joseph Cannon survived the test.
Mr Gaetz said on Sunday he believed he had enough Republican support to oust Mr McCarthy.
“The only way Kevin McCarthy is speaker of the House at the end of this coming week is if Democrats bail him out,” he told CNN.