(Reuters) - U.S. President Donald Trump welcomed a decision by the National Football League to fine teams if players on the field refuse to stand for the national anthem, saying in an interview broadcast on Thursday that if they do not want to stand, perhaps they should not be in the United States.

FILE PHOTO: Indianapolis Colts players kneel during the playing of the National Anthem before the game against the Cleveland Browns at Lucas Oil Stadium in Indianapolis, IN, U.S., September 24, 2017. Mandatory Credit: Brian Spurlock-USA TODAY Sports/File Photo

Last season some NFL players took a knee during the anthem to protest police shootings of unarmed black men, sparking a controversy. Trump denounced the players as unpatriotic and repeatedly demanded an end to such protests.

Under the new policy unveiled on Wednesday by NFL Commissioner Roger Goodell, teams will be fined if players on the field fail to stand during “The Star-Spangled Banner.” Players who choose not to stand may remain in the locker room until the anthem is finished.

“I think that’s good. I don’t think people should be staying in locker rooms but still I think it’s good,” Trump told Fox News in an interview taped on Wednesday and broadcast on Thursday.

“You have to stand, proudly, for the national anthem. Or you shouldn’t be playing, you shouldn’t be there. Maybe you shouldn’t be in the country,” Trump said.

The protests, in a league where African-Americans make up the majority of players, continued for much of the past season, with some players kneeling when the anthem was played and others standing arm-in-arm in solidarity.

The NFL Players Association, the athletes’ union, said it was not consulted on the new policy and may issue a challenge should it violate the collective bargaining agreement.

NAACP President and Chief Executive Officer Derrick Johnson called on the league to rescind the policy and said team owners must not “fold” to the Trump administration by denying players the ability to raise questions around aggressive policing.

“This is not about disrespecting the flag, this is about using their platform to advocate a social justice position that all citizens should be treated with human dignity even when pulled over by police,” Johnson told Reuters in an interview.

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Trump, Johnson said, has demonstrated “time and time again that he lacks the intellectual curiosity to really address serious issues confronting this nation.”

‘RESPECT AND LOVE’

The American Civil Liberties Union (ACLU) launched a petition calling on the NFL to respect its players’ voices and rescind the new policy.

The ACLU said that Trump and the NFL’s mostly white and wealthy team owners saw the protests as a sign of disrespect.

“But respect and love for America doesn’t require blindness to America’s failure to honor its promise of racial justice and equality - failures that are made even more evident each time the police murder a person of color and get away with it,” the ACLU said in a statement.

The civil rights organization National Action Network said it was planning a rally with community leaders and clergy to take place on Friday outside NFL headquarters in New York City.

Democratic U.S. Senator Ben Cardin said the Republican president’s words were “inflammatory,” but not unexpected, and added that Trump’s suggestion that players should be ousted is “never going to be acceptable to me and, I think, to many Americans.”

“This country stands for the constitutional protections of the First Amendment, the right to freedom of speech. That’s what this country is about,” Cardin told CNN in an interview.

Still, Cardin added, “what the NFL is doing right now is moving in the right path,” noting that employers can establish reasonable standards over employees’ expression.

Baltimore Ravens head coach John Harbaugh said in a statement that he believes in standing for the American flag.

“To me, the flag represents the ideas and the ideals that make us America,” Harbaugh said. “I also believe in the freedoms the flag represents and that people can speak for themselves.”