A 97-year-old World War II veteran is being applauded after taking a stand against Donald Trump and kneeling in solidarity with NFL players protesting police violence against black people.

The US President has repeatedly called for any professional footballer to be fired if they take a knee during the national anthem played before games.

But hours before players across the league kneeled in defiance of Mr Trump on Sunday, John Middlemas staged a protest in his back garden.

Brennan Gilmore, Mr Middlemas’ grandson, posted a photo of the Missouri farmer, quoting him as saying: “Those kids have every right to protest.”

Speaking to CBS News, Mr Gilmore said: "We were having a discussion about it and you know, the idea that people were pointing to disrespecting military servicemen as justification for these comments. He wanted to send a message of solidarity to them.”

The tweet has been shared more than 150,000 times with many describing Mr Middlesmas, who served in the US Navy for 21 years, as “America’s grandpa”.

The war veteran’s stand against the President comes as Mr Trump shared a supporter’s tweet suggesting footballers who kneel during the national anthem were disrespecting the memory of Pat Tillman, a former NFL player who died in Afghanistan after joining the military.

Mr Gilmore said his grandfather had the “moral authority to speak more than basically anyone about what our veterans fought for”.

“I think it really resonated with people,” he added.

Mr Trump has repeatedly condemned players protesting police brutality before games since bringing up the issue at a campaign rally in Alabama on 22 September.

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The 70-year-old told supporters any “son of a b****” who decided to kneel should be “fired”. “That owner, they don't know it [but] they'll be the most popular person in this country,” he said

The protest movement has been gaining momentum ever since Colin Kaepernick, an NFL quarterback currently without a team, sat down during the national anthem at a pre-season game with the San Francisco 49ers in 2016.