Last updated on .From the section American football

Protests that took place at NFL games on Sunday were "unlike anything I've ever seen before", according to two-time Super Bowl winner Osi Umenyiora.

Players for teams throughout the league, including a match at Wembley, knelt during the US national anthem.

US President Donald Trump said on Friday that those who protest should be sacked or suspended.

Last year, quarterback Colin Kaepernick knelt for the anthem in protest against racial injustice and police brutality.

At Wembley more than 20 players and staff from Baltimore Ravens and Jacksonville Jaguars knelt or linked arms during the anthem.

Similar protests took place at every NFL game in the United States.

But owners of Nascar teams have threatened to fire employees who protest, while ice hockey's Pittsburgh Penguins have accepted President Trump's invitation to the White House to mark their championship win.

Trump 'threw down a challenge'

London-born former New York Giants player Umenyiora, who now works as a pundit for the BBC, said: "I was expecting something - we all were - because the president's remarks were shocking.

"As president of the United States, you just can't say these things. He threw down a challenge to the NFL players.

"He called them sons of bitches and I don't remember him saying that about the white supremacists.

"He has some friends who are owners of NFL teams and maybe he thought that they would back him up, but the opposite happened."

Mr Trump attacked dissenting players at a rally in Alabama

Trump told a Republican rally in Alabama on Friday that the protests showed "disrespect of our heritage".

The former host of The Apprentice said: "Wouldn't you love to see one of these NFL owners, when somebody disrespects our flag, to say, 'Get that son of a bitch off the field right now, out, he's fired. He's fired'."

"You know, some owner is going to do that. And that owner, they'll be the most popular person in this country."

On Sunday, he tweeted: "If NFL fans refuse to go to games until players stop disrespecting our flag and country, you will see change take place fast. Fire or suspend!"

Trump Tweeted his response to the protests on Sunday.

He later tweeted a call for the NFL to change its policy around the anthem

Trump's remarks sparked an online debate, with people supporting the president using the hashtag #BoycottNFL and those backing the protesting players using the hashtag #TakeAKnee.

Although after San Francisco 49ers player Kaepernick refused to stand to protest against the treatment of black Americans last year, #BoycottNFL was also used to show support for him.

Basketball star LeBron James, who has won four Most Valuable Player awards in the NBA, described Trump as a "bum" over comments he made about fellow player Steph Curry.

Trump said the Golden State Warriors were no longer invited to the White House after their star player Curry, 29, said he did not want to attend "to show that we won't stand for the things [the president] has said".

Nascar bosses would not tolerate protests

Richard Petty won the Daytona 500 a record seven times

NHL team the Pittsburgh Penguins confirmed they would attend the White House but the Stanley Cup champions said in a statement they "respect the rights of other individuals and groups to express themselves as they see fit".

Two Nascar teams were, however, firm in their stance against the protests and threatened to fire employees who used the national anthem as a means of protest.

At a race meeting in New Hampshire, Richard Petty - who co-owns a team in his name - said those not standing for the anthem "ought to be out of the country".

Petty, 80, is statistically the most successful driver in Nascar history and added: "If they don't appreciate where they're at… what got them where they're at? The United States."

Nascar is second to only the NFL external-link in terms of attracting television viewers in the US.

Asked what he would do if one of his staff protested during the anthem, another co-owner Richard Childress said: "Get you a ride on a Greyhound bus when the national anthem is over.

"I told them anyone who works for me should respect the country we live in. So many people have gave their lives for it. This is America."

On Monday, President Trump tweeted: "So proud of Nascar and its supporters and fans. They won't put up with disrespecting our country or our flag - they said it loud and clear!"

The sport later issued a statement which read: "Sports are a unifying influence in our society, bringing people of differing backgrounds and beliefs together.

"Our respect for the national anthem has always been a hallmark of our pre-race events. Thanks to the sacrifices of the many we live in a country of unparalleled freedoms and countless liberties, including the right to peacefully express one's opinion."

'I would have taken a knee'

New England Patriots players were among those to protest during the US national anthem on Sunday. Quarterback Tom Brady stood but locked arms with team-mate Phillip Dorsett.

Umenyiora, who retired in 2015, said NFL players should be praised for their positive influence on fans.

The 35-year-old said: "It is beyond belief that the president, whose number one job is to uphold and protect the constitution, is trying to attack the right to free speech and protest.

"I am surprised there were any players left standing during the anthems, to show that man how wrong he was.

"If I was still playing I would have taken a knee, I am absolutely certain about that.

"The athletes in the NFL have a tremendous influence but the president wanted them to shut up and stay silent like they are dummies."

The Kaepernick effect

Kaepernick is still a free agent

Kaepernick has been without a team since leaving the 49ers last season, with some suggesting that potential clubs have been put off signing him because of his protests. external-link

"So much credit and love goes to Colin Kaepernick for what he did last year and what he sacrificed," Umenyiora said.

"We all saw police brutality and mistreatment of African Americans and he had the nerve to make a stand.

"If it wasn't for him we wouldn't be having this conversation now.

"Kaepernick will be looked at as a hero - maybe not right now, but he will be."

Trump comments a 'slap in the face'

Jacksonville Jaguars owner Shad Khan (centre), who also owns Championship football club Fulham, displayed his unity with players before the match at Wembley

Jaguars owner Shad Khan, who donated $1m (£740,000) to Trump's presidential campaign, linked arms with his players before the game against Baltimore at Wembley, which Jacksonville won 44-7.

He said: "I met with our team captains prior to the game to express my support for them, all NFL players and the league following the divisive and contentious remarks made by President Trump, and was honoured to be arm in arm with them, their team-mates and our coaches during our anthem."

Players from three teams - the Pittsburgh Steelers, Seattle Seahawks and Tennessee Titans - stayed in their locker rooms when the anthem was played.

A statement from the Seahawks players read: "As a team, we have decided we will not participate in the national anthem. We will not stand for the injustice that has plagued people of colour in this country.

"Out of love for our country and in honour of the sacrifices made on our behalf, we unite to oppose those that would deny our most basic freedoms."

NFL Players' Association president Eric Winston said Trump's comments were "a slap in the face to the civil rights heroes of the past and present".

National Football League commissioner Roger Goodell said players had raised millions of dollars for recent disaster relief efforts and were involved in community programmes.

"There is no better example than the amazing response from our clubs and players to the terrible natural disasters we've experienced over the last month," he said.

"Divisive comments like these demonstrate an unfortunate lack of respect for the NFL."

Thirty of the 32 teams in the NFL released official statements in response to Trump.

New England Patriots CEO Robert Kraft, who also donated to Trump's election campaign, said he was "deeply disappointed" by the comments, and that he supported players' rights to protest.

Miami Dolphins founder and owner Stephen Ross said the US needed "unifying leadership right now, not more divisiveness".

Jed York, CEO of the 49ers, said he would continue to support his players, calling the comments "callous and offensive".

How teams reacted before Sunday's NFL games