US President Donald Trump has praised the "great anger" shown by NFL fans over the weekend amid the ongoing controversy surrounding the national anthem.

More than 200 players, coaches and owners kneeled or boycotted pre-game performances of the anthem over the weekend as a mark of protest for the 'Black Lives Matter' movement.

Trump has accused protesting players of "disrespecting" the country with their actions and has called upon fans to boycott games and owners to fire any "son of a bitch" that protests in future.

Last night the entire Dallas Cowboys team took to their knees ahead of their game at the Arizona Cardinals, prompting boos from around the University of Phoenix Stadium.

Taking to Twitter today, Trump wrote: "Ratings for NFL football are way down except before game starts, when people tune in to see whether or not our country will be disrespected!

"The booing at the NFL football game last night, when the entire Dallas team dropped to its knees, was loudest I have ever heard. Great anger.

"But while Dallas dropped to its knees as a team, they all stood up for our National Anthem. Big progress being made-we all love our country!"

NBA star LeBron James has hit out at Trump for his comments, suggesting that the protest may find its way to the NBA this season.