British police are investigating bomb threats made on Twitter against three women journalists.
Guardian columnist Hadley Freeman, Independent columnist Grace Dent and Europe editor of Time magazine Catherine Mayer all received the tweet which Ms Dent took a screen grab of and posted for her Twitter followers to see.
It was from anonymous user @98JU98U989, and said: "A BOMB HAS BEEN PLACED OUTSIDE YOUR HOME. IT WILL GO OFF AT EXACTLY 10.47PM ON A TIMER AND TRIGGER DESTROYING EVERYTHING".
A spokesman for the Metropolitan Police said: "We can confirm that the MPS has received allegations relating to bomb threats sent to a number of females on Twitter."
The spokesman said enquiries are continuing and so far there have been no arrests.
After receiving the threat, Ms Freeman said on Twitter that she was calling the police, adding: "If it's illegal to threaten to bomb an airport, it's illegal to threaten to bomb me."
Ms Dent described the threat as a "new low".
Meanwhile, over 100,000 people have signed a petition calling on Twitter to step up its procedures for dealing with abuse after a feminist campaigner and a female MP were targeted.
Caroline Criado Perez and Walthamstow MP Stella Creasy have complained about receiving vicious tweets on the site in the past week.
A Scotland Yard spokesman said a 25-year-old man arrested by Northumbria Police on suspicion of harassment was released on bail.
Ms Criado Perez, from north London, found herself at the centre of a public furore after she launched a campaign to have a woman's picture printed on a new sterling banknote.
Ms Creasy was also subjected to abusive tweets when she spoke out in support of the campaigner.
Twitter has announced plans to include a button for reporting abuse within every tweet - something which is already available on its iPhone app.
But critics argue this does not go far enough and only directs users to the existing reporting form which, they claim, is too long and impractical.
Del Harvey, Twitter's director for trust and safety, admitted it was not the company's policy to automatically report threatening or abusive messages to police.
The website does not hold information to reveal the location a message has been sent from and therefore cannot identify the correct local police force, Ms Harvey said.
She also revealed she had received messages threatening to rape her on "multiple platforms across multiple sites on the internet" but chose not to prosecute.