A growing list of major law firms on Tuesday said they are suspending or rethinking contributions by their political action committees following the Jan. 6 attack on the U.S. Capitol by President Donald Trump supporters seeking to overturn the results of the 2020 election.

The firms pausing donations include St. Louis-based Bryan Cave Leighton Paisner, which in the 2019-2020 election cycle gave to U.S. Senator Josh Hawley of its home state Missouri and to Senator Ted Cruz of Texas. Squire Patton Boggs, Baker & Hostetler, Hogan Lovells, Holland & Knight, Buchanan Ingersoll & Rooney, Cozen O'Connor and Kansas City, Missouri-based Polsinelli also said they were pausing PAC contributions.

Squire Patton Boggs, a Washington, D.C., mainstay known for its lobbying work, was the first to announce its decision publicly, saying Tuesday morning that it will suspend PAC contributions and review its PAC policies.

"Squire Patton Boggs believes that there is no room for violence in our society, including in the context of political protests, and that a peaceful transition of power is fundamental to our democratic system of government," the firm said in a statement.

Holland & Hart pledged specifically not to support candidates who sought to block President-elect Joe Biden's victory. The firm said its PAC "will not contribute to the election campaigns of any legislator who voted to object to the certification of the 2020 Presidential election."

Other firms stopped short of halting donations but vowed to scrutinize their giving. Akin Gump Strauss Hauer & Feld, a top lobbying firm, said its PAC will consider the Jan. 6 riot and "false rhetoric questioning the legitimacy of the recent elections as part of a broad array of factors" in contribution decisions. Kelley Drye & Warren said it will review its criteria for PAC contributions. Covington & Burling made a similar pledge.

Husch Blackwell, another large Kansas City, Missouri, firm, said Tuesday its PAC contributes to "candidates from both parties based on a wide variety of factors and the interests of our clients" and that it "will continue to weigh those factors in the future."

Well over a dozen law firm PACs donated to members of Congress in the 2020 election cycle who last week voted against certifying Biden's Electoral College win.

Cruz and Hawley led those efforts in the Senate, in a long-shot bid to overturn the results of the Nov. 3 election, which Trump has repeatedly and without evidence claimed was rigged.

The claims of voter fraud whipped Trump's supporters into a frenzy, which culminated on Jan. 6 with hundreds of people storming the U.S. Capitol building as Congress was certifying the results. The attack forced Congress to evacuate, delaying the certification, and left five people dead.

Since then several major U.S. businesses, including AT&T Inc and Delta Air Lines Inc, have paused PAC donations and pledged to review their contribution policies.

OpenSecrets data shows that at least four law firms, including Bryan Cave, Husch Blackwell and Nelson Mullins, gave to Hawley in the 2019-2020 election cycle. At least five firms, including Bryan Cave, Baker & Hostetler, Locke Lord and McGuireWoods, gave to Cruz.

More than ten law firm PACs in the 2019-2020 election cycle gave to House members that voted against certifying Biden's win, OpenSecrets shows, including Hogan Lovells, Duane Morris and Biden's outside counsel law firm Covington.

Representatives for Cruz and Hawley did not immediately respond to requests for comment. Representatives for several law firms whose PACs donated to objecting lawmakers did not immediately provide comment. A representative for Duane Morris declined to comment.

UPDATE: This story has been updated three times to include actions and statements by additional firms regarding their PAC giving.

(Additional reporting by Nate Raymond)