WASHINGTON (AP) — It's a tumultuous time for House Republicans, and leadership elections this coming week may only heighten the disarray. Dissatisfied lawmakers are casting about for new choices and a surprise longshot challenger is emerging in the speaker's race.

The upheaval reflects a caucus ever more divided in the week since House Speaker John Boehner stunned Capitol Hill by resigning under conservative pressure. And it comes as a long list of weighty and polarizing issues loom on Congress' agenda, including raising the federal borrowing limit to avoid a market-shattering default, and paying the bills to keep the government running.

Rep. Jason Chaffetz of Utah, the brash 48-year-old chairman of the high-profile House oversight committee, intends to challenge the prohibitive favorite for speaker, Majority Leader Kevin McCarthy of California, Republican aides said Friday.

Yet it's not clear that the hard-liners who ousted Boehner, R-Ohio, and view McCarthy with suspicion would flock to Chaffetz, given that as committee chairman he has enforced leadership initiatives such as punishing lawmakers who buck the party position.

The leadership elections are Thursday.

"It would be hard to replace John Boehner with someone who also kicks people off committees for their votes," sniped Rep. Thomas Massie, R-Ky., who is backing another candidate, Rep. Daniel Webster, R-Fla.

That raises the prospect of more unrest — and potentially even more candidates — before votes for the new leadership team are cast.

"Until we decide that we're going to function as a team instead of as a series of groups trying to enforce their agenda on the majority of the House, then we're going to have this treadmill kind of a thing where we're just walking faster and faster but not actually physically moving," said Rep. Frank Lucas, R-Okla.

The well-liked McCarthy has been endorsed by Boehner, but some of the hard-line conservatives who forced Boehner out immediately questioned whether his leadership would be any different. Their concerns were compounded when, a day after announcing his candidacy for speaker, McCarthy boasted that the House Benghazi committee can take credit for Hillary Rodham Clinton's slipping poll numbers.

McCarthy backtracked, but it took him two days and the gaffe allowed Democrats to claim that the committee is a political witch hunt — not a fact-finding mission into the deaths of four Americans at the U.S. mission in Benghazi, Libya, as Republicans had long asserted.

Chaffetz was one of the loudest critics of McCarthy's comments on Benghazi, publicly calling on McCarthy to apologize for "a total mischaracterization" of the committee's work.

He's now converting that sentiment into a challenge against McCarthy for speaker, according to three Republican aides with knowledge of the situation who demanded anonymity to confirm Chaffetz's plans ahead of an announcement. Chaffetz' office did not respond to requests for comment, but the congressman is to appear on "Fox News Sunday" to discuss his plans.

Chaffetz has led high-profile investigations into the Secret Service, Planned Parenthood and other issues, but he is unlikely to outmaneuver McCarthy for the speaker's job. Republicans of all ideologies, especially hardline conservatives, are plainly dissatisfied with their choices for the leadership jobs with public approval of Congress at rock bottom and voters demanding results in challenges to President Barack Obama.

The two candidates for majority leader to replace McCarthy — House Majority Whip Steve Scalise of Louisiana and Budget Committee Chairman Tom Price of Georgia — also are established figures who don't meet some lawmakers' desire for a new direction. Yet Republicans in Congress are short on dynamic, broadly popular and experienced leaders who could move naturally into the top jobs. Some of those who exist — like Rep. Paul Ryan of Wisconsin — have opted against running for leadership.

In all likelihood McCarthy will be the next speaker and Scalise or Price the next majority leader of the House, putting new faces in Congress' top jobs but perhaps doing little to correct the institution's overall dysfunction.

"Some faceless bureaucrat has more legislative authority than the entire United States Congress," said hardline Rep. Steve King, R-Iowa, who is hoping more choices emerge for the top jobs. "That's the situation we're in and we need to put that back in order, and we need a speaker and majority leader that will collaborate on a plan to do that."

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Associated Press writers Alan Fram, Mary Clare Jalonick and Matthew Daly contributed to this report.