Donald Trump
Donald TrumpReuters

Robert Greenblatt, chairman of NBC Entertainment, has slammed Republican presidential nominee Donald Trump as "toxic" and "demented" in a private Facebook post that became public and quoted by The Associated Press on Tuesday.

Greenblatt's post refers to a "sad state of affairs thanks to a pompous businessman turned reality TV star" who thinks that speaking his mind is "refreshing."

"It's actually corrosive and toxic because his 'mind' is so demented; and his effect will unfortunately linger long after he's been told to get off the stage," the executive said in the post Monday, which doesn't refer to Trump by name.

Trump was the star of NBC’s "Apprentice" reality show.

Greenblatt does not oversee NBC News or its campaign coverage but his remarks likely will give critics of the media an opening for attack, noted AP.

Earlier this week, Trump blasted the media for its unfair coverage of his campaign, saying at a rally, "Maybe we'll start thinking about taking away their press credentials. When they write dishonest stories we should be a little bit tough."

Greenblatt’s post, according to AP, also derided the business mogul's ratings prowess, writing that Trump's show "consistently ran LAST in its time period, by the way."

While "The Apprentice" was a hit for NBC when it began airing in 2004, the most recent season finale of "Celebrity Apprentice," the latest incarnation, finished in fourth place when it aired in February 2015.

A person familiar with Greenblatt's private page said Tuesday the post came from the NBC executive. The person, who lacked authority to discuss the matter publicly, spoke on condition of anonymity.

Trump's campaign did not immediately return a message from AP seeking comment.

NBC, part of Comcast Corp. subsidiary NBCUniversal, declined comment Tuesday. Comcast did not immediately respond to a request for comment.