U.S. President Donald Trump on Monday reiterated his criticism of NFL players who knelt during the national anthem, pushing back against suggestions that race drove his calls for those football players to be fired.

Trump wrote on Twitter that his objection "has nothing to do with race. It is about respect for our Country, Flag and National Anthem. NFL must respect this!"

With his attacks on activist athletes, Trump again plunged into the middle of his favourite kind of drama β€” personal, aggressive, culturally volatile and entirely of his own making. For four days, the provocateur president has drawn criticism from the worlds of politics and sports for saying that football players who kneel during the national anthem should be fired.

The conflict peaked Sunday with Trump's remarks, which had the effect of uniting a newly minted opposition coalition that included a growing number of players and coaches, as well as some owners who have backed the president.

On Monday morning, Trump continued to defend the scrap β€” which prompted about 200 players to stand, kneel or raise their fists during the national anthem at games β€” writing: "Many people booed the players who kneeled yesterday (which was a small percentage of total). These are fans who demand respect for our Flag!"

Trump bashes NFL players as protests grow | 'This has nothing to do with race'2:46

NFL spokesperson Joe Lockhart on Monday morning in a conference call stood up for the players' rights to peacefully protest what they view as racial inequality and police brutality.

"Everyone should know, including the president, this is what real locker-room talk is," Lockhart said, in an apparent reference to the Access Hollywood tapes in which Trump bragged about sexually assaulting women.

Trump returned to the fray Monday night, tweeting, "Tremendous backlash against the NFL and its players for disrespect of our Country."

Earlier, referring to the NFL protests, the Canadian Football League's communications director Paulo Senra said in a statement, "Regardless of whether we liked it or agreed with it, we would absolutely respect our players' right to express their views in this way, which is peaceful and does not disrupt our game in any way."

Quoting the line, "true north strong and free" from O Canada, Senra said that if those words, "are to be truly celebrated, we must honour their meaning, not just their singing."

Showing solidarity: Interview with Calgary Stampeder James Vaughters5:59

Speaking to reporters on Sunday night in New Jersey, Trump also offered his own take on the players and coaches who chose to lock arms on the field during the anthem, describing it as a display of "solidarity" that he approved of. And he pushed back against the suggestion that his critique could inflame racial tensions, arguing: "I never said anything about race."

But Trump has had a history of engaging in racially fraught battles, from his promotion of the false story that the nation's first black president, Barack Obama, was not born in the United States, to his campaign proposal to temporarily ban Muslims from the United States. He drew condemnation last month for saying "both sides" were to blame for violence between white supremacists and their opposing demonstrators during clashes in Charlottesville, Va.

Seahawks Titans Football

Officials stand on the sideline during the playing of the national anthem before an NFL football game between the Seahawks and the Tennessee Titans on Sunday. Neither team came out onto the field for the anthem. (Mark Zaleski/Associated Press)

White House spokesperson Sarah Huckabee Sanders said it was a mistake to try to conflate the anthem controversy with the response to Charlottesville, saying "we certainly respect the rights that people have" to protest.

Original protest tied to police shootings

Trump's feud with athletes came as the president prepared to sell a tax overhaul plan this week, aiming to build support for his top legislative priority, as well as health-care legislation brought forward by Republicans in the Senate.

Sanders rejected the notion in a Monday news briefing that Trump wasn't paying attention to the administration's pressing issues.

"I certainly don't think talking about the American flag is a distraction for the president of the United States," she said, adding that composing a tweet takes very little time.

The initial protest was inextricably linked with the issue of race, specifically, police shootings of minority suspects.

The anthem protest started when former San Francisco 49ers quarterback Colin Kaepernick refused to stand during the anthem on Aug. 26, 2016. The move received little notice during or after the game, but when Kaepernick was asked about it in the ensuing days, he said it was a protest of police treatment of minorities, mentioning police officers "getting paid leave and getting away with murder."

The 49ers defended their players' freedom of expression at the time, saying "we recognize the right of an individual to choose to participate, or not, in our celebration of the national anthem."

Broncos Bills Football

Buffalo Bills players kneel during the playing of the national anthem prior to an NFL game against the Denver Broncos on Sunday. (Jeffrey T. Barnes/Associated Press)

Some other NFL players and those in other sports, notably U.S. women's soccer player Megan Rapinoe, followed Kaepernick's lead in kneeling during the anthem in 2016.

When asked about the race relations component of Kaepernick's initial protest, Sanders said the focus of the anthem protests "has long since changed," without offering any explanation as to what she meant.

Kaepernick and the 49ers parted ways after the season and he has yet to find NFL employment, although commissioner Roger Goodell has denied the quarterback is being blackballed, saying each individual team makes decisions about its roster.

Kaepernick has said he would stand for the anthem if signed by a team for this season because his actions have already caused awareness and started a conversation, although those comments were made before Sunday's groundswell of support.

Only a handful of NFL players had been continuing Kaepernick's protest this season, but Trump reignited the issue during a campaign rally in Huntsville, Ala., on Friday evening before thousands of cheering fans.

Colin Kaepernick Rally

Supporters of unsigned NFL quarterback Colin Kaepernick arrive for a rally Aug. 23, near NFL headquarters in New York. (Craig Ruttle/Associated Press)

Amid comments about the Senate race to replace Jeff Sessions, now his attorney general, Trump 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."

The crowd chanted: "U.S.A, U.S.A."

Sanders did not respond directly to a question about Trump's pejorative language on Friday.

Patriots' owner pushes back on Trump

The president's delving into the NFL protests started by Kaepernick brought new attention and angered many players who took one insult as a personal attack on their mothers. 

NFL owners, several of whom donated money to Trump's campaign, distanced themselves this time. New England Patriots owner Robert Kraft, who gave a Super Bowl ring to Trump, said on Sunday night he was "deeply disappointed by the tone of the comments made by the president."

He added that there is "nothing more divisive than politics" and said he supported players' "right to peacefully affect social change and raise awareness in a manner that they feel is most impactful."

Trump shrugged off the comments, saying: "He's a good friend of mine."

Trump continued his salvos against athletes on Saturday when he rescinded a White House invitation for the Golden State Warriors, the NBA champions led by black players, over Stephen Curry's criticism.

Warriors coach Steve Kerr said: "Not surprised. He was going to break up with us before we could break up with him."

Reactions to Trump's anti protest tweets0:40

The president on Monday also used his favourite social media platform to point to fans who booed players who knelt during Sunday's NFL games along with auto racing fans of NASCAR who "won't put up with disrespecting our Country or our Flag."

Driving legend Richard Petty, said on Sunday any member of his NASCAR team would be fired if they chose to protest the anthem.

At least one group allied with Trump was quick to take action. The pro-Trump political non-profit America First Policies released a Facebook ad with the tagline "Turn off the NFL."

With files from CBC News