Players in the National Football League (NFL) have taken part in a wave of protests at US President Donald Trump's "offensive" and "divisive" comments.
In a growing row with the sports world, Mr Trump insisted that players who failed to stand during the national anthem should be fired or suspended.
Fans in many stadiums booed their own teams as players or entire teams knelt or linked arms in response.
Sunday's protests are the largest of their kind since they began last year.
Players have been protesting at racial injustice and perceived police violence.
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Mr Trump's calls to fire players taking part in such protests were supported by many, but have proved deeply divisive.
To a crowd of cheering supporters on Friday, Mr Trump asked: "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... he is fired'?"
He was referring to a widespread protest movement in the sport started by player Colin Kaepernick, who began sitting or kneeling during the anthem last year in protest against police brutality and the treatment of black Americans.
Sports players responded with widespread protest action during the weekend's sporting action.
On Saturday night, the Oakland Athletics' Bruce Maxwell became the first Major League Baseball player to kneel in protest during the anthem.
During Sunday's NFL games:
- Neither the Seattle Seahawks nor the Tennessee Titans turned out for the national anthem before kick-off at their game, hours after the Pittsburgh Steelers did the same in Chicago
- The Chicago Bears stood on the sidelines with their arms locked, as did New England Patriots star quarterback Tom Brady and teammates at another game. Some Green Bay Packers and Cincinnati Bengals players also linked arms
- The anthem singer at the Seahawks-Titans game kneeled at the end of he performance, as did singer at the Lions-Falcons game, who also raised his fist
- Fans booed their own teams at some games as players protested - including at the Titans and Patriots games
- Philadelphia Eagles fans clashed with protesters ahead of a game in their home city against the New York Giants
- Jacksonville Jaguars owner Shahid Khan - who donated $1m (£740,000) to the Trump campaign - locked arms with his players in an unusual scene, as owners rarely join players on the pitch.
The NFL itself has criticised Mr Trump's remarks, with commissioner Roger Goodell saying "divisive comments like these demonstrate an unfortunate lack of respect".
Eric Winston, president of the NFL Players' Association, said Mr Trump's comments were "a slap in the face to the civil rights heroes of the past and present".
Mr Trump is also facing criticism after withdrawing an invitation to the White House to basketball champions the Golden State Warriors after one player, Stephen Curry, said he did not want to attend.
Curry - NBA's top performer in 2015 - said he wanted to show that he and other players did not stand for "the things that he's said and the things that he hasn't said in the right times".
"Going to the White House is considered a great honor for a championship team," Mr Trump tweeted afterwards. "Stephen Curry is hesitating, therefore invitation is withdrawn!"
The Golden State Warriors said the team had clearly understood "that we are not invited" to the White House but would visit Washington DC on its own "to celebrate equality, diversity, and inclusion".