Dozens of N.F.L. players around the country kneeled and linked arms with their teammates during the pre-game national anthem on Sunday, responding to President Trump’s repeated comments over the weekend that criticized that exact form of protest. The entire Pittsburgh Steelers team, save one, sat in the locker room during the anthem; other teams, like the Cleveland Browns, knelt in large numbers. Tom Brady, perhaps the most famous football player in the country and an apparent Trump supporter, linked arms with his teammates in a show of solidarity:

In Detroit, where the Atlanta Falcons played the Lions, singer Rico Lavelle concluded his performance of the national anthem by taking a knee.

Early Sunday morning Trump continued the controversy he kicked off during a speech in Alabama on Friday, firing off a few early morning tweets that called for N.F.L. fans to boycott “boring games” so that the players will stop “disrespecting our Flag & Country.” He also repeated his demand that players who choose to protest should be either suspended or fired.

Treasury Secretary Steven Mnuchin appeared on ABC’s This Week to discuss the protests, and said that the N.F.L. should have rules against this kind of protest. “I think what the President is saying is that the owners should have a rule that players should have to stand in respect for the National Anthem. This isn’t about Democrats, it’s not about Republicans, it’s not about race, it’s not about free speech,” he said. “They can do free speech on their own time. That this is about respect for the military and first responders in the country.”

On Saturday the controversy spread to more professional leagues, after Trump attempted to un-invite Stephen Curry from a White House visit and Lebron James responded in a tweet calling the president “u bum.“ That evening, Oakland A’s catcher Bruce Maxwell became the first Major League Baseball player to kneel during the anthem.

At the start of Sunday morning’s game between the Baltimore Ravens and Jacksonville Jaguars, held in London, members of both teams knelt, their teammates linking arms in solidarity.

It wasn’t just the players who were speaking out against Trump throughout the weekend. Though the president enjoyed support from numerous N.F.L. owners, with several of them donating to his campaign, multiple owners issued statements condemning his remarks. Among them was New England Patriots chairman and C.E.O. Robert Kraft, who counts himself as a personal friend of Trump’s. “I am deeply disappointed by the tone of the comments made by the President on Friday,“ he said in a statement. “I am proud to be associated with so many players who make such tremendous contributions in positively impacting our communities. Their efforts, both on and off the field, help bring people together and make our community stronger.”

Trump’s speech in Huntsville, Alabama, in which he said N.F.L. leagues should be allowed to “get that son of a bitch off the field“ when players kneel during the anthem, was ostensibly in support of Alabama Senate candidate Luther Strange. He also took time in the speech to claim that penalties for hard hits—aimed at reducing the amount of concussions and debilitating brain injuries in the sport—were “ruining the game.“