Speaking at a rally in Huntsville, Alabama, on Friday night in support of Republican Senate primary runoff candidate Luther Strange, President Donald Trump deviated from politics to voice his disapproval of NFL players kneeling down in protest during the national anthem.

The president urged team owners of such players to fire them for disrespecting the national anthem. 

"Wouldn’t you love to see one of the NFL owners, when somebody disrespects our flag, to say 'Get that son of a b----- off the field right now'" Trump said to thunderous applause and cheers.

"You know, some owner ... is going to say, 'That guy who disrespects our flag, he’s fired,'" Trump said.

Trump also said that people should "pick up and leave" during such protests in order to change players' disrespectful practices. "I guarantee things will stop," he said.

Though Trump refrained from naming any player during his speech, his remarks were likely referring to former 49ers quarterback Colin Kaepernick, who attracted nationwide attention for refusing to stand during the national anthem before a preseason game last.

He said he did it to protest the wrongdoings against African Americans and minorities in the U.S.

"I am not going to stand up to show pride in a flag for a country that oppresses black people and people of color." Kaepernick told NFL Media in August 2016. "To me, this is bigger than football and it would be selfish on my part to look the other way. There are bodies in the street and people getting paid leave and getting away with murder."

Kaepernick's protest had received both support and backlash, CNN reported.

However, Trump's comments Friday did not find support among Twitter users, with many former and current NFL players criticizing the president and asking him to stick to politics and not interfere in sports.

Chris Conley, Kansas City Chiefs wide receiver, tweeted: "Stick to sports boy... Sit down and do what your told. Say or do something we don’t like and your fired."

Shannon Sharpe, a former football tight end who played for the Denver Broncos and Baltimore Ravens, wrote: "Tell 45 to stick to politics. I go to politics to get away from sports."

Some even said that Trump was being harsher on NFL players than he has ever been on Russian President Vladimir Putin, Al Qaeda or white supremacist groups.

After Kaepernick's protests last year, several players have followed suit. Following the violence in Charlottesville, Virginia, last month, Seattle Seahawks defensive end Michael Bennett sat with a towel draped over his head during the anthem at a game. He had said he planned to continue the protest for the rest of the season.

His decision, he said, was influenced by the far-right violence that took place in Charlottesville, a report said.

"The last week, with everything that’s been going on in the last couple months – especially after the last couple days seeing everything in [Charlottesville] Virginia... I just wanted to be able to continue to use my platform to be able to speak on injustice," Bennett said.