The Pittsburgh Steelers remained in the locker room while members of the Chicago Bears stood locked arm-in-arm during the national anthem ahead of Sunday's game at Soldier Field.
"We're not going to play politics," Steelers head coach Mike Tomlin told CBS ahead of the game. "We're football players, we're football coaches. We're not participating in the anthem today - not to be disrespectful to the anthem, but to remove ourselves from the circumstance."
The team's decision came amid a growing controversy in the wake of comments President Donald Trump made Friday slamming NFL players who participate in protests during the anthem and calling on team owners to fire them.
"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,'" Trump said at a rally in Alabama.
His comments sparked a firestorm of criticism from several angles, with professional athletes across multiple leagues, NFL owners and even league Commissioner Roger Goodell joining in a chorus to call Trump's remarks "divisive" and "disrespectful."
The Chicago Bears initially remained quiet on the issue, deferring to Goodell's statement Saturday, but chairman George McCaskey issued a response Sunday, ahead of the game against the Steelers and after Trump doubled down on his remarks in a series of early-morning tweets.
"The Chicago Bears are proud to support our players, coaches and all members of our organization to bring peace and unity together through football," he said.
"What makes this the greatest country in the world are the liberties it was founded upon and the freedom to express oneself in a respectful and peaceful manner. Through important dialogue with our players and team, this divisive political situation has unified our franchise for the present and the future."
At the first football game of the day in London, at least seven members of the Baltimore Ravens and more than a dozen Jacksonville Jaguars took a knee during the anthem as the other players stood with arms locked together.
The rest of the day's games saw more protests, with the Seattle Seahawks and the Tennessee Titans later joining the Steelers in remaining in their respective locker rooms as a team during the anthem before their game.
"These are very divisive times for our country and you know, for us as a football team, it's about us remaining solid. We're not gonna be divided by anything said by anyone," Tomlin said.
"People shouldn't have to choose," he continued. "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."
One member of the Steelers did choose to stand for the anthem Sunday despite his team's decision, as offensive tackle Alejandro Villanueva - a former Army ranger - stood just outside the players' tunnel with his hand over his heart.
Protests of this nature started when then-San Francisco 49ers quarterback Colin Kaepernick sat, then kneeled, for the playing of the anthem beginning in Aug. 2016 to call attention to the oppression of minorities across the United States.
Kaepernick's actions sparked a national conversation that several other NFL players have joined, protesting on multiple occasions and continuing even after Kaepernick became a free agent at the end of the season.
Soldier Field was the site of one such demonstration last September, when members of the Philadelphia Eagles raised their fists in the air during the anthem ahead of their game against the Bears.