US President Donald Trump's continued demands on Sunday that NFL owners fire or suspend players who kneel during the national anthem were met with defiance as teams and players knelt and locked arms in solidarity.

More than 100 players across the country on Sunday knelt during the national anthem or remained sitting in their locker rooms in protest. Most teams in the early afternoon games locked arms in solidarity, with at least three team owners joining their players.

The President had earlier in the day continued a three-day crusade to pressure the league to fire players who take a knee to protest against police violence towards minorities. Trump has poured fuel on the flame of a simmering culture war and has further pushed sports deep into the political arena.

"If NFL fans refuse to go to games until players stop disrespecting our Flag & Country, you will see change take place fast," Trump wrote. "Fire or suspend!"