NFL players used the national anthem to show their defiance to US President Donald Trump's criticism, with at least 100 players kneeling or sitting in the latest protest and one team staying in the locker room.
Most teams in the early afternoon games on Sunday locked arms in solidarity.
At least three team owners joined their players.
More than 100 players sat or knelt, the form of protest started last season by former San Francisco 49ers quarterback Colin Kaepernick, who was campaigning against what he saw as civil rights abuses in the United States.
On Saturday, Trump suggested NFL owners whose players decide to take a knee during the national anthem fire them.
Players and owners united in defiance of Trump who said he didn't watch any NFL games on Sunday and denied his comments were racially motivated.
"This has nothing to do with race or anything else. This has to do with respect for our country and respect for our flag," he said.
The Pittsburgh Steelers remained in the locker room as the national anthem played before their game with the Chicago Bears.
Coach Mike Tomlin stood by himself on the sideline.
How each team would observe the national anthem emerged as the centre of attention on this NFL Sunday in the wake of Trump's critical remarks toward players who don't stand for the anthem.
Tomlin had said before the game that Pittsburgh's players would remain in the locker room and that "we're not going to let divisive times or divisive individuals affect our agenda."
Tomlin added that the Steelers made this choice "not to be disrespectful to the anthem but to remove ourselves from this circumstance. People shouldn't have to choose."
The protestations began as the NFL made their now annual pilgrimage to London.
There about two dozen players, including Baltimore Ravens linebacker Terrell Suggs and Jacksonville Jaguars running back Leonard Fournette, took a knee during the playing of the national anthem before the start of the game at Wembley Stadium.
Other players on one knee during the performance included Ravens linebacker CJ Mosley, wide receiver Mike Wallace and safety Lardarius Webb as well as Jaguars linebacker Dante Fowler, defensive tackle Calais Campbell, defensive end Yannick Ngakoue and cornerback Jalen Ramsey.
No players were kneeling during the playing of the British national anthem, God Save the Queen.
