Donald Trump says Arnold Schwarzenegger did not leave The New Celebrity Apprentice voluntarily but was forced to go because of the show's "pathetic" ratings.
The Hollywood star revealed he was leaving the US programme after just one series following a number of high-profile spats with the president, who remains an executive producer.
Schwarzenegger blamed the show's "baggage" for his decision to leave and accused Mr Trump of driving away viewers with his continued involvement, which left a "bad taste".
But the president hit back and denied he had a hand in the star's departure.
He tweeted: "Arnold Schwarzenegger isn't voluntarily leaving the Apprentice, he was fired by his bad (pathetic) ratings, not by me. Sad end to great show."
In an interview with Empire, Schwarzenegger said people "don't want to participate as a spectator or as a sponsor or in any other way support the show".
He added: "It's a very divisive period now and I think this show got caught up in all that division."
In January, Trump taunted the former California governor over the show's latest series in a tweet.
He referred to himself as a "ratings machine" and said Schwarzenegger had been "swamped" by comparison.
The tycoon later said the show had been a "total disaster" since Schwarzenegger took over, with the actor responding by suggesting they should switch jobs .
"Everyone, from the celebrities to the crew to the marketing department, was a straight 10," said Schwarzenegger as he announced his departure.
"I would absolutely work with all of them again on a show that doesn't have this baggage."