WASHINGTON (AP) — Republican Rep. Matt Gaetz filed a resolution late Monday to oust Kevin McCarthy as speaker, setting up a likely showdown vote in the House in the days ahead.

The far-right Republican from Florida has for months threatened to use the procedural tool — called a motion to vacate — to try to strip McCarthy of his office. Those threats escalated over the weekend after McCarthy relied on Democrats to provide the necessary votes to fund the government.

In an earlier speech on the House floor, Gaetz demanded McCarthy disclose the details of a supposed deal the speaker made with the White House to bring forward legislation to help fund the war in Ukraine during funding negotiations.

“It is becoming increasingly clear who the speaker of the House already works for and it’s not the Republican Conference,” Gaetz said in his speech, hours before he filed the resolution.

Brushing off the threat, McCarthy told reporters earlier at the Capitol, “I’m focused on doing the work that has to be done.” He added that there was “no side deal” on Ukraine, noting he has not spoken to Biden.

A motion to vacate is a rare and strong procedural tool that has only been used twice in the past century against Republican speakers. But in recent years, conservatives have wielded the motion as a weapon against their leaders.

In January, McCarthy, hoping to appease some on the hard right like Gaetz as he fought to gain their vote for speaker, agreed to give as few as five Republican members the ability to initiate a vote to remove him. But when that wasn’t good enough for his critics, he agreed to reduce that threshold to one — the system that historically has been the norm.

That decision has set McCarthy up for the ultimate test of his leadership as he will now have to rely on Democrats to withhold their support for any effort to force his removal.

The motion Gaetz introduced is a privileged resolution, a designation that gives it priority over other measures. The next step is for House leaders to schedule a vote on the resolution within two legislative days.

However, there are several procedural motions that members of either party could introduce to slow down or stop the process altogether. If those tactics were to fail, and his resolution came to the floor for a vote, it would take a simple majority of the House — 218 votes, when no seats are vacant — to remove McCarthy from his post.