It started early, in London.

Just before 9:30 a.m. Eastern time, some Baltimore Ravens and Jacksonville Jaguars knelt during "The Star-Spangled Banner" while other players locked arms with one another and team executives on a National Football League Sunday suddenly draped in political controversy.

At 1 p.m., similar scenes played out from Philadelphia to Buffalo to Detroit, as athletes delivered a stark visual rebuke to President Trump's sharp criticism of athletes who have staged silent protests during the anthem. Later in the day, more demonstrations and symbolic statements spread across the league, drawing in players and executives who had not spoken before.

"We've got a lot of prideful guys in our league, and when you're pushed or come after ours, guys will respond," said Malcolm Jenkins, an Eagles safety who has long raised his fist during the national anthem to protest how minorities are treated by police and the criminal justice system.  "It's one thing to have a fan say something on social media, but to have high-ranking officials come out and single guys out, I think that's one of the things that let players know that their voices are needed."

Arriving on a fall Sunday, when so much of the country devotes itself to forgetting real-world worries and rallying behind the home team, the protests represented one of the most sweeping and visible statements yet opposing the president.

They also marked another moment when politics — and sharp cultural divisions inflamed by Trump — infused another aspect of American life. While the anthem protests have long been a subject of debate, they moved from subplot to center stage, joining late-night talk shows and the Emmys in the vortex of controversies the president has seemed to relish.

On Meet the Press, pundits talked about the NFL. On sports radio, updates about protests preceded the latest scores.

Trump kept pushing. In one of several tweets on the subject, he said that the initial demonstrations showed "Great solidarity for our National Anthem," and that "Standing with locked arms is good, kneeling is not acceptable. Bad ratings." But he later added, "Sports fans should never condone players that do not stand proud for their National Anthem or their Country. NFL should change policy!"

While Trump has long thrived on conflict, his latest blast saw him taking on a new class of rival. The athletes who hit back, including NBA stars like LeBron James and Stephen Curry, have global followings that cross political and economic divides.

"U bum," James tweeted in part to his 38.5 million followers. "Going to White House was a great honor until you showed up!"

The clash, and the president's focus on it, came even amid growing fears of conflict with a nuclear North Korea, as people in Puerto Rico struggle without power, and as a long-stated Republican goal, repealing the Affordable Care Act, threatens to again crumble. Late Sunday, Trump added to the mix by announcing details of new travel restrictions into the United States.

Yet Trump used a Friday night rally in Alabama, and numerous tweets Sunday, to slam the NFL and players who have protested during the national anthem by either kneeling or holding their fists aloft.

"Wouldn't you love to see one of these NFL owners, when somebody disrespects our flag, to say, 'Get that son of a bitch off the field right now, out, he's fired. He's fired,' " Trump told roaring supporters Friday.

The disputes came as an ABC News/Washington Post poll released Sunday found that 66 percent of the public believes Trump has done more to divide the country than unite it.

His comments seemed to embolden players and league officials, including some who demonstrated for the first time.

In Philadelphia, all but one Eagles player locked arms during the national anthem, joined by team owner Jeffrey Lurie, team executives and members of the military and police. (The one Eagle who didn't join in, linebacker Mychal Kendricks, said he was late getting to the field and not making a political statement.)

Eagles wide receiver Torrey Smith raised his fist, something he hadn't done before.

"If the leader of our country feels that way, we have to continue to protest, and we have to continue to work to change our communities," Smith said after the game. He told reporters that his father had served 25 years in the Army but, as a truck driver, faces some of the same racial inequalities that so many protesters are trying to combat.

Giants defensive end Olivier Vernon knelt during the anthem, also the first time he has done so.

"I don't care if you're the president or not," Vernon told reporters. "You ain't my president."

In Detroit, singer Rico LaVelle ended his rendition of the anthem by kneeling and putting his fist in the air. Some teams skipped the anthem entirely.

Robert Kraft, the New England Patriots owner who donated $1 million to Trump's inauguration, issued a statement saying he was "deeply disappointed" by Trump's tone.

"There is no greater unifier in this country than sports, and unfortunately, nothing more divisive than politics," Kraft said.

Trump allies and some political analysts suggested the debate would help the president, who has long thrived by lending a voice to his supporters' grievances, refusing to bow to what they see as liberal orthodoxy.

"I think that the president is standing with the vast majority of Americans who believe that our flag should be respected," said Marc Short, Trump's director of legislative affairs, on Meet the Press.

At the Eagles game, Shawn McGill, a Giants fan from Langhorne, said players were disrespecting the anthem. He noted that he was wearing a blue jersey in a sea of green. But for "The Star-Spangled Banner," "we all stood for the same thing."

Others firmly backed the players' rights to protest, including Kirk Singleton, 52, of Reading. Nearby, Jeff Alper, also 52, from Linwood, N.J., disagreed.

The two Eagles fans briefly debated the issue, but after a few moments shook hands — and told each other to enjoy the game.

Staff writers Les Bowen and Mike Sielski contributed to this article.