(Reuters) - Several dozen NFL players, fewer than last week, chose to sit or kneel during the U.S. national anthem at the start of games on Sunday, a day after President Donald Trump again demanded an end to a protest he sees as a sign of disrespect for the flag.

NFL Football - Miami Dolphins vs New Orleans Saints - NFL International Series - Wembley Stadium, London, Britain - October 1, 2017 Miami Dolphins players kneel during the U.S. national anthem before the match Action Images via Reuters/Paul Childs

The symbolic gesture, initiated last year by then-San Francisco 49ers quarterback Colin Kaepernick, snowballed last week following calls by Trump for team owners to fire athletes who sat out the anthem.

On Sunday, more than 40 players, many of them on the 49ers, sat or knelt on one knee during renditions of the “Star-Spangled Banner” in the 15 National Football League games, compared with 180 players in all 16 games a week earlier.

Some African-American players have adopted the practice of kneeling during the anthem to protest against police treatment of racial minorities.

Critics including Trump object to any protest, regardless of its merits, during a ceremony meant to honor the flag and military veterans.

Some 30 members of the 49ers knelt before a game in Arizona on Sunday, and their general manager and chief executive stood behind them, The Mercury News in the San Francisco Bay area reported.

In Seattle, several members of the Seahawks sat out the national anthem, while their opponents, the Indianapolis Colts, linked arms along the sidelines.

In other games, players on some teams went to one knee before the anthem was played and then rose as a team when the song began. Players on a handful of teams stood with raised fists during parts of the anthem or after it, according to a team-by-team rundown from sports television network ESPN.

At London’s Wembley Stadium, where the NFL’s first game was played on Sunday, three members of the Miami Dolphins knelt as U.S. singer Darius Rucker performed the U.S. anthem. All of the other uniformed Dolphins and their opponents, the New Orleans Saints, stood along the sidelines, many with their right hands over their hearts.

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The three players who had knelt stood for the British anthem, “God Save the Queen.”

CONTROVERSY GRIPS NFL

‘Before last weekend’s games, Trump wrote a series of tweets that fueled the debate over whether the players should be able to protest during the anthem.

The controversy quickly enveloped the most popular U.S. sports league, preoccupied the news media and became a hot topic of discussion at bars and offices across the country.

The Saints and some other teams sought a compromise stance, kneeling in unison before the anthem and standing together during the song. The aim was to show respect for both the flag and the position taken by the protesters.

“The decision to kneel ... prior to the anthem and then everyone stand up together, number one, it shows solidarity and unity for us as a team,” Saints quarterback Drew Brees said. “Listen, it pays respect to all.”

During the past week, Trump kept up a drumbeat of criticism of the protesting players.

“Very important that NFL players STAND tomorrow, and always, for the playing of our National Anthem,” he wrote on Twitter on Saturday. “Respect our Flag and our Country!”

On Tuesday, Trump called on the NFL to ban players from kneeling in protest at games during the anthem.

“The NFL has all sorts of rules and regulations,” he wrote. “The only way out for them is to set a rule that you can’t kneel during our national anthem!”

The theme may play well with Trump’s conservative base at a time when the Republican president is grappling with North Korea’s nuclear threats, a humanitarian crisis in hurricane-struck Puerto Rico and an investigation of Russian meddling in the 2016 election and a healthcare struggle in Congress.

Outside Wembley Stadium on Sunday, not all British fans supported the players’ protests.

“I think everyone has the right to protest, but I think you have to choose your stage wisely,” said Laura Williams, who works in healthcare. “I think you risk upsetting more people than it’s worth.”

Mark Dodson, an engineer, said, however, the protests were “absolutely a global initiative” and “a sign of solidarity between different races, different backgrounds, different everything basically, which is great to see.”