A Muslim convert threatened to drop a bomb on an MP's house and "show her what it's like to murder innocents" after she voted in favour of Syria air strikes.
Craig Wallace, 23, launched a tirade of abuse on Facebook aimed at Tory MP Charlotte Leslie, who represents Bristol North West.
"I'm going to smash her windows then drop a bomb on her house while she's tucked up in bed. You dirty f****** pig-shagging slut," he wrote.
"I'm going to find her and show her what it's like to murder innocents. You dirty pig-f****** whore," he said in a second post on December 3, the day after MPs voted to authorise the air strikes.
Wallace, who calls himself Muhammad Mujahid Islam on Facebook, has a string of convictions for violent offences including possession of a knife.
He converted to Islam while in prison serving a sentence of almost five years for attempted robbery.
Three weeks after he was released he posted the messages on a thread of comments on the UK Truth Movement Facebook page.
Wallace, of Teignmouth Road in Willesden Green, north London, pleaded guilty to sending threatening communications at Hendon Magistrates' Court. He was remanded in custody and will be sentenced on December 30.
Ms Leslie's father saw the comments online and reported them to police.
Wallace claimed he was "venting his anger" and had not had any sleep because he had been "protesting for two or three days".
District Judge Mark Jabbitt said: "What's absolutely clear is that your language and expressions about this MP Ms Leslie, who you have no knowledge of, went beyond any sort of legitimate comment or protest on an extremely serious issue.
"What you did was personalised it and used really the most vile, insulting and threatening language imaginable on a forum."
He ordered a full risk assessment report on Wallace and expressed concern that he was not being formally supervised after his release from prison.
Abu Sayeed, defending, said Wallace has mental health issues and had not been taking his anti-psychotic medication.
"He has co-operated fully with the police and expressed remorse and regret," he added.
"He made the comments to vent his anger.
"Mr Wallace is a Muslim convert, he converted while serving his last sentence.
"He feels very passionately about the bombing in Syria and the vote recently taken in Parliament.
"He had been out with other protesters and was protesting for two or three days and not had much sleep and hadn't taken his medication."
Wallace has never met Ms Leslie and thought the page was a "closed group", Mr Sayeed said.
"In the current climate people would have been fearful of his comments," he added.
A number of other MPs, many of them in the Labour Party, have complained to police that they had received death threats after voting in favour of airstrikes on Islamic State (IS) in Syria.
Neil Coyle, the MP for Bermondsey and Old Southwark, said police had stationed extra officers outside his surgery after he received an apparent death threat on social media, while Labour Rochdale MP Simon Danczuk has spoken out about receiving an apparent death threat on Facebook after he voted in favour of the military action.