The US House of Representatives has voted to create an independent commission to probe the deadly January 6 attack on the Capitol by supporters of former president Donald Trump.
A significant number of Republicans defied party leaders' attempts to block it.
Over the past two days, House Republican Leader Kevin McCarthy and Senate Republican Leader Mitch McConnell worked to kill a bipartisan bill to establish the commission to investigate the violence that left five people dead.
The House voted 252-175 to approve the commission, which was styled after the September 11, 2001, panel that probed attacks on the United States.
The bill now goes to the Senate where its future is unclear.
The solid number of Republicans voting for the independent investigation - 35 out of 211 - signalled some cracks in the party's defence of Trump on a key vote.
Trump opposes the creation of a commission.
All 10 of the House Republicans who voted to impeach Trump in January voted for the commission.
House Majority Leader Steny Hoyer, a Democrat, said McCarthy - a close ally of Trump - "got what he asked for" in a compromise on the structure of the commission, which would be charged with wrapping up its investigation by December 31.
Earlier in the day, McConnell announced he would not support the House bill, calling it "the House Democrats' slanted and unbalanced proposal" and saying existing congressional investigations are sufficient.
In the 50-50 Senate - controlled by Democrats only because Vice President Kamala Harris can cast tie-breaking votes - Republicans can block the legislation. At least 60 votes are needed to advance most bills.
"There will continue to be no shortage of robust investigations," said McConnell, who in January said that the mob that attacked the Capitol was "fed lies" and "provoked" by Trump and others.
The 10-member commission would produce a public report including recommendations for preventing another Capitol attack. It would be charged with examining security and intelligence failures surrounding the riot in which Trump's supporters, after he delivered an incendiary speech, interrupted the formal congressional certification of Democrat Joe Biden's victory in the November election.
During debate, Republican Representative John Katko said "an independent 9/11-style review is critical for removing the politics around January 6".
Katko helped craft the legislation with House Homeland Security Committee Chairman Bennie Thompson, a Democrat.
The House bill, unveiled last week, would give Republicans equal power with Democrats in appointing commissioners and equal say over witnesses.
Australian Associated Press