Lawmakers announced Friday a deal to form a 9/11-style bipartisan commission to investigate the violent Jan. 6 attack on the U.S. Capitol by hundreds of Donald Trump supporters after a monthslong stalemate over the size and scope of the panel.

Under the terms of the agreement , negotiated by Reps. Bennie Thompson (D-Miss.) and John Katko (R-N.Y.), Congress would form a 10-person commission, with five members appointed by Democrats and five by Republicans . The commissioners must have significant expertise in the areas of law enforcement, civil rights, civil liberties, privacy, intelligence, and cybersecurity and cannot currently hold public office.

The panel would be charged with investigating the circumstances of the Jan. 6 attack as well as the influencing factors that may have provoked it. Subpoenas issued by the commissioners would need approval from both the chair and vice-chair of the panel. And the commission would issue a final report by the end of the year.

But in a sign that the commission may not be a done deal, Minority Leader Kevin McCarthy (R-Calif.), the top Republican in the House, told reporters he hadnt seen the agreement and didnt sign off on it.

Then you cant do that, McCarthy said Friday when told the commissions sole focus appears to be on the events of Jan. 6. Thats very concerning to me.

McCarthy, a loyal ally of former President Donald Trump, has pushed to expand the scope of the commission to investigate unrelated racial justice protests during the previous year. He may also end up being the target of the commission itself: as Trump supporters stormed the Capitol on Jan. 6, McCarthy phoned Trump and begged him to call them off .

Democrats will likely have the votes to pass the Thompson-Katko agreement in the House as soon as next week. But with McCarthy already expressing skepticism, its not clear whether his GOP colleagues in the Senate will go along.

Both Senate Minority Leader Mitch McConnell (R-Ky.) and Sen. Roy Blunt (R-Mo.) have said that focusing on Jan. 6 would be too narrow and that the investigation should be left to congressional committees that have already held hearings on the Jan. 6 attack.

If there was one, it would just be another 12 months or something before we did the things that we need to figure out how to do right now, which is a better intel structure, a better decision-making structure, more training and more [police] recruitment, Blunt said last month.