(NewsNation) — Fox News has told former anchor Tucker Carlson he breached his contract by launching a new show on Twitter, sources confirmed to NewsNation.

Carlson and the network parted ways earlier this year following a $787 million settlement in a defamation lawsuit brought by Dominion Voting Systems. The company alleged Fox News tarnished its reputation by publishing and promoting lies that the 2020 election was stolen.

Axios first reported Fox’s breach of contract claim. Carlson’s lawyers told Axios that any legal action against him would be a violation of his First Amendment rights.

In his first show since leaving Fox News, Carlson published a 10-minute video Tuesday on Twitter discussing the war in Ukraine and UFOs. He expressed sympathy for Russian President Vladimir Putin and called Ukrainian President Volodymyr Zelenskyy the “shifty dead-eyed Ukrainian friend in the tracksuit.”

Carlson’s new show, “Tucker on Twitter,” is a stripped-down version of his former prime-time program that drew some 3 million viewers to Fox on a nightly basis. The first episode on Twitter has been viewed nearly 92 million times since it was posted.

At the time of Carlson’s departure, Fox News said: “FOX News Media and Tucker Carlson have agreed to part ways. We thank him for his service to the network as a host and prior to that as a contributor.”

Carlson and his lawyers are also accusing Fox News of breaching a contract, Axios previously reported. They argue that the network committed fraud when it made promises to Carlson that were intentionally broken.