"While listening to our National Anthem, LeBron James disrespects our Country," Trump said in a Truth Social post accompanied by a video showing James moving his body during the singing of the anthem. "LeBron James should apologize to all of those Great American Warriors and Heroes who died for the American Flag, and all that our Country stands for!"
The clip Trump shared showed James standing in line with the members of the Philadelphia 76ers, swinging his arms in a warmup-type stretch and performing basketball shooting movements.
A representative for the 76ers did not immediately respond to a request for comment.
Trump has repeatedly criticised athletes for their behaviour during pre-game renditions of the US national anthem, notably beginning with NFL quarterback Colin Kaepernick's kneeling protest in support of racial justice.
Trump canceled a planned White House visit of the Super Bowl champions Philadelphia Eagles in 2018 after the team disagreed with his call for players to stand during the anthem.
James became a leading voice in the Black Lives Matter movement in 2020 and has frequently supported progressive issues as he ascended to the top of the NBA's all-time scoring list.