A former Fox News contributor is accusing the network of deliberately keeping him away from segments on Russia because he wouldn't unconditionally support President Trump.

Retired Lt. Col. Ralph Peters, who left Fox News as a contributor with a fiery resignation letter earlier this month, made the new claims in an op-ed for The Washington Post on Friday.

He asserted that the network "preaches paranoia, attacking processes and institutions vital to our republic and challenging the rule of law."

Peters said that he remained with the network despite his concerns over its coverage because he "rationalized that I could make a difference by remaining at Fox and speaking honestly."

"I was wrong," he added.

Peters wrote that he was not invited on segments about Russia despite being "the one person on the Fox payroll who, trained in Russian studies and the Russian language, had been face to face with Russian intelligence officers in the Kremlin and in far-flung provinces."

"Listening to political hacks with no knowledge of things Russian tell the vast Fox audience that the special counsel's investigation was a 'witch hunt,' while I could not respond, became too much to bear. There is indeed a witch hunt, and it's led by Fox against [special counsel] Robert Mueller," he wrote.

The network rejected Peters' claims.

"There is no truth to the notion that Ralph Peters was 'blocked' from appearing on the network to talk about the major headlines, including discussing Russia, North Korea and even gun control recently. In fact, he appeared across both networks multiple times in just the past three weeks," a Fox News spokesperson said in a statement to The Hill.

Peters in the op-ed also ripped Fox for its "assault on our intelligence community," targeting network host Lou Dobbs specifically.

"With my Soviet-studies background, the cult of Trump unnerves me. For our society's health, no one, not even a president, can be above criticism - or the law," Peters said.

The former network analyst quit earlier this month, calling Fox News a "propaganda machine."

He was also suspended from Fox News for two weeks in 2015 for using a profanity to criticize then-President Obama.

-Updated 1:10 p.m.