NFL players responded in full force Sunday after President Trump repeatedly called for swift punishment against those who chose to protest by not standing during the national anthem.

Demonstrations spread throughout the league as many players broke out of their routine by joining the protests or engaging in team-wide displays of unity.

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Several players from the Buffalo Bills, Denver Broncos, New York Giants, Detroit Lions, New England Patriots, New Orleans Saints and Atlanta Falcons were among those who chose not to stand for the anthem. The Miami Dolphins, Tampa Bay Buccaneers, Minnesota Vikings, Philadelphia Eagles, Chicago Bears, Indianapolis Colts and New York Jets stood with arms locked, though some players from those teams chose to kneel.

Multiple members of the Miami Dolphins wore shirts that read "#IMWITHKAP," referencing former San Francisco 49ers quarterback Colin Kaepernick, before their game against the New York Jets. Kaepernick, who began the protests last year by choosing not to stand during the anthem and remains a free agent, said he wanted to speak out against racial injustice and police brutality.

In Sunday's first game, several players from the Baltimore Ravens and Jacksonville Jaguars either knelt or locked arms on their respective sidelines in solidarity during the national anthem at Wembley Stadium. Included among them was Jags owner Shahid Khan, who locked arms with tight end Mercedes Lewis and linebacker Telvin Smith.

Khan was one of seven owners to donate $1 million to President Donald Trump’s inauguration festivities. Also kneeling with Baltimore was former Ravens linebacker Ray Lewis.

The Pittsburgh Steelers chose not to have players on the sidelines during the national anthem before a game against the Chicago Bears.

"We're not going to play politics. We're football players, we're football coaches," Tomlin said. "We're not participating in the anthem today - not to be disrespectful to the anthem, but 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 teammate who chooses not to."

At a rally on Friday in Alabama, President Trump said, "Wouldn’t you love to see one of these NFL owners, when somebody disrespects our flag, to say, 'Get that son of a b---- off the field right now. Out. He's fired. He's fired!"

Trump has not backed down. On Sunday he said, "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! …NFL attendance and ratings are WAY DOWN. Boring games yes, but many stay away because they love our country. League should back U.S."

Players, commissioners and owners from multiple sports lashed out against the President over the weekend. The issue grew when Trump withdrew an invitation to the White House for the NBA champion Golden State Warriors, specifically pointing to star Steph Curry. Later, the college basketball national champion North Carolina Tar Heels said they would not visit the White House, citing scheduling conflicts.