Donald Trump is demanding an apology from ESPN for Jemele Hill's comments referring to him as a "white supremacist" ... and claims the network is suffering from getting too political.

POTUS fired off a tweet at the network Friday morning ... just days after White House press secretary Sarah Huckabee Sanders called Hill's comment a "fireable offense."

"ESPN is paying a really big price for its politics (and bad programming). People are dumping it in RECORD numbers. Apologize for untruth!" Trump tweeted.

Along with calling Trump a "white supremacist" ... Hill referred to him as "the most ignorant, offensive president of my lifetime."

Hill hasn't deleted the tweets ... but has addressed the controversy, saying "my comments on Twitter expressed my personal beliefs. My regret is that my comments and the public way I made them painted ESPN in an unfair light.

"My respect for the company and my colleagues remains unconditional."