Former Trump adviser Roger Stone on Sunday posted a message on Instagram calling for former CIA Director John Brennan to be hanged.

"This psycho must be tried, charged, convicted, and hung for treason," read the message with a picture of Brennan.

Stone is currently awaiting the start of his trial after being charged with obstruction, witness tampering and lying to investigators by the Mueller probe.

Brennan is one of Trump's staunchest critics, and a frequent target of the president.

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Roger Stone, a former adviser to President Donald Trump, posted a story to Instagram saying that former CIA director John Brennan should be "hung for treason."

The post was later removed from Instagram, reportedly for violating its policies.

Stone posted the story Sunday which contained a picture of Brennan and the message "this psycho must be tried, charged, convicted, and hung for treason."

He is longtime associate of Trump who advised the real estate mogul's presidential campaign until August 2015, and has a reputation for controversial posts on Instagram.

The message was first reported by CNN's Brian Stelter. The network's national security analyst Sam Vinograd tweeted that Instagram told her Instagram took the post down after she reported it.

David Martosko, the US Political Editor for DailyMail.com, posted an image from the story showing Stone's attack on Brennan:

Stone's attorney, Robert Buschel, did not immediately return a request for comment.

Stone was one of the Trump associates charged by former special counsel Robert Mueller's probe into Russian interference.

In January he was indicted on counts of obstruction, witness tampering and lying to investigators. Stone, a veteran political operative and self-declared "dirty trickster," has said the charges are politically motivated.

He is scheduled to stand trial in Washington DC in November.

It's not the first time Stone's incendiary social media posts since his arrest have created controversy.

In February Judge Amy Berman placed a gagging order on Stone after he posted an image on Instagram depicting her in the crosshairs of a rifle.

Among other messages Stone posted on his instagram feed on Sunday was a sartorial tip, a picture of his wife, and praise for the hairstyle Trump briefly sported at an event in Virginia on Sunday.

"I've known @realdonaldtrump for 40 years. I don't think he's ever looked better !" wrote Stone.

John Brennan is one of the president's staunchest critics, and in August 2018 the Trump administration revoked his security clearance, citing "erratic conduct and behavior.'