Kevin McCarthy elected Republican U.S. House speaker

Republican Kevin McCarthy was elected speaker of the U.S. House of Representatives early on Saturday.

The 57-year-old Californian suffered one final humiliation when Representative Matt Gaetz withheld his vote on the 14th ballot as midnight approached, prompting a scuffle in which fellow Republican Mike Rogers had to be physically pulled away.

McCarthy's victory in the 15th ballot brought an end to the deepest congressional dysfunction in over 160 years. But it sharply illustrated the difficulties that he will face in leading a narrow and deeply polarised majority.

He won at last on a margin of 216-212. He was able to be elected with the votes of fewer than half the House members only because six in his own party withheld their votes - not backing McCarthy as leader, but also not voting for another contender.

"I'm glad that it's over," McCarthy told reporters shortly after the vote.

McCarthy agreed to a demand by hardliners that any lawmaker be able call for his removal at any time. That will sharply cut the power he will hold when trying to pass legislation on critical issues including funding the government, addressing the nation's looming debt ceiling and other crises that may arise.

"We got the things that are transformational," said Republican Representative Ralph Norman, who voted to back McCarthy after opposing him for much of the week.

Republicans' weaker-than-expected performance in November's midterm elections left them with a narrow 222-212 majority, which has given outsized power to the right-wing hardliners who have opposed McCarthy's leadership.

Those concessions, including sharp spending cuts and other curbs on McCarthy's leadership, could point to further turbulence in the months ahead, especially when Congress will need to sign off on a further increase of the United States' $31.4 trillion borrowing authority.