The owners of the Baltimore Ravens, the Super Bowl champion New England Patriots and other teams on Sunday joined a chorus of NFL executives criticizing President Donald Trump's suggestion that they fire players who kneel for the national anthem.

The statements, from Patriots owner Robert Kraft and Ravens owner Steve Bisciotti, contrasted a morning tweet from Mr. Trump and further escalated the political drama of the league's game day, which was expected to be one of the most-watched for non-sporting reasons in years.

Bisciotti said he "100 percent" supports his players' decision to kneel during the national anthem. At least seven of them did, joined by more than a dozen Jacksonville Jaguars, before the teams played at Wembley Stadium in London.

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Kraft, who has been a strong backer of the president, expressed "deep disappointment" with Mr. Trump and said politicians could learn much from the unifying spirit of a competitive, team-oriented enterprise like football.

"Our players are intelligent, thoughtful, and care deeply about our community and I support their right to peacefully affect social change and raise awareness in a manner that they feel is most impactful," Kraft said in a statement.

A mounting number of teams were issuing statements in support of their players late Saturday and into Sunday.

Pittsburgh Steelers coach Mike Tomlin told CBS Sports that his team would remain in the locker room during the national anthem on Sunday. "We're not going to play politics. We're football players, we're football coaches. We're not participating in the anthem today," Tomlin said.

He added, "Not to be disrespectful to the anthem, to remove ourselves from the circumstance. People shouldn't have to choose. If a guy wants to go about his normal business and participate in the anthem, he shouldn't be forced to choose sides. If a guy feels the need to do something he shouldn't be separated from his teammates who chooses not to. So we're not participating today."

Steelers head coach Mike Tomlin reveals to @JamieErdahl that the team will not be participating in today's national anthem. pic.twitter.com/5zihPWQsMv — NFLonCBS (@NFLonCBS) September 24, 2017

Green Bay Packers President and CEO Mark Murphy said it was unfortunate that Mr. Trump used his "immense platform" to make "divisive and offensive" statements toward players and the NFL.

"We strongly believe that players are leaders in our communities and positive influences," Murphy said in a statement. "As Americans, we are fortunate to be able to speak openly and freely.

Statement from #Patriots Chairman & CEO Robert Kraft: pic.twitter.com/f5DJeK0Woj — New England Patriots (@Patriots) September 24, 2017

Statement from Arthur Blank: pic.twitter.com/20DH3DHc4e — Atlanta Falcons (@AtlantaFalcons) September 23, 2017

Statement from Miami Dolphins Owner and Founder of Ross Initiative in Sports for Equality (RISE) Stephen Ross. pic.twitter.com/6W3mXwJO6M — Miami Dolphins (@MiamiDolphins) September 23, 2017

Statement from Buffalo Bills Owners Terry and Kim Pegula. pic.twitter.com/i3D5xzBBSn — Buffalo Bills (@buffalobills) September 24, 2017

A statement from Seahawks President Peter McLoughlin pic.twitter.com/vGzMj0TFmz — Seattle Seahawks (@Seahawks) September 24, 2017

In a statement released on Sunday, Detroit Lions owner and chairwoman Martha Firestone Ford said the NFL has been a "unifying force in our country and impactful change has and hopefully will continue to be the result of peaceful expression, done so in order to highlight social injustices of all kind."

She added, seemingly pointing to Mr. Trump's statements, that "negative and disrespectful comments suggesting otherwise are contrary to the founding principles of our country, and we do not support those comments or opinions."

Quarterback Colin Kaepernick started the kneeling movement last year when he played for the San Francisco 49ers, refusing to stand during "The Star-Spangled Banner" to protest the treatment of black people by police. Kaepernick became a free agent and has not been signed by a new team for this season.

Without identifying Kaepernick, Mr. Trump aimed a Friday talk at a Huntsville, Alabama, rally at those players who have knelt for the anthem.

Mr. Trump said to loud applause "wouldn't you love to see one of these NFL owners, when somebody disrespects our flag, you'd say, 'Get that son of a b---- off the field right now. Out! He's fired."

Again in a Sunday morning tweet, Mr. Trump urged his supporters to take action: "If NFL fans refuse to go to games until players stop disrespecting our Flag & Country, you will see change take place fast. Fire or suspend!"

Mr. Trump's remarks provoked team owners and the NFL to stridently defend the sport and its players.

Patrick Omameh of the Jacksonville Jaguars kneels during the U.S. national anthem on Sept., 24, 2017. Action Images via Reuters/Andrew Boyers

The Buffalo Bills were bothered enough by the situation to hold a voluntary team meeting on Saturday, with players, coaches, staff and ownership all taking part.

"Our goal was to provide open dialogue and communication. We listened to one another. We believe it's the best way to work through any issue we are facing, on and off the field," owners Terry and Kim Pegula said in a statement distributed by the Bills. "President Trump's remarks were divisive and disrespectful to the entire NFL community, but we tried to use them as an opportunity to further unify our team and our organization. Our players have the freedom to express themselves in a respectful and thoughtful manner and we all agreed that our sole message is to provide and to promote an environment that is focused on love and equality."

NFL Commissioner Roger Goodell, who has taken heat for Kaepernick's struggle to find a team, quickly condemned Mr. Trump's comments, saying "divisive comments like these demonstrate an unfortunate lack of respect for the NFL, our great game and all of our players, and a failure to understand the overwhelming force for good our clubs and players represent in our communities."

Mr. Trump responded with a tweet Saturday, writing that Goodell should "tell them to stand!"

Roger Goodell of NFL just put out a statement trying to justify the total disrespect certain players show to our country.Tell them to stand! — Donald J. Trump (@realDonaldTrump) September 23, 2017

The NFL Players Association, a union for NFL players, said that they "no longer can afford to stick to sports."

"We will never back down," executive director DeMaurice Smith said in a statement. "We no longer can afford to stick to sports."