Police are investigating bomb threats made on Twitter against female journalists.
Guardian columnist Hadley Freeman, Independent columnist Grace Dent and Europe editor of Time magazine Catherine Mayer all received the tweet which Dent took a screen grab of and posted for her Twitter followers to see.
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, 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."
Dent described the threat as a "new low".
Meanwhile, over 100,000 people have signed a petition calling on Twitter to beef 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.
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.
A change.org petition calling for Twitter to take a stronger stance has drawn more than 100,000 signatures.
The petition states: "Abuse on Twitter is common, sadly too common. And it frequently goes ignored. We need Twitter to recognise that its current reporting system is below required standards."
Ms Criado Perez, 29, said Twitter needed to "get a grip" on security after she received a barrage of abusive messages, as it emerged bosses were likely to face a grilling from MPs.
She said the social network was ill-equipped to handle episodes of sustained abuse and needed to work more closely with police to deal with internet trolls.
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.
Ms Harvey told BBC Radio Five Live: "We don't have that much information about our users compared with other platforms.
"We don't always have that information about where the message came from.
"If somebody called you and said, 'I'm going to come over and beat you up', you don't expect the phone company to contact the police. You certainly expect them to work with police."
Asked whether she would be happy with Twitter's response if she received abusive messages, Ms Harvey replied: "I actually have received tweets like that and I can tell you that if I had felt that it was something that I wanted to prosecute then I would have gone to law enforcement directly about it.
"It's awful and I certainly wouldn't wish receiving that kind of content on anyone and that's part of the reason I want to get this right and I want us to work on improving how we handle these things."
Ms Criado Perez met Twitter directors on Monday night along with Ms Creasy, who received a similar torrent of abusive messages after she offered support to the freelance journalist.
"This will have been a wake-up call for Twitter," Ms Criado Perez said.
"It will hopefully have led them to realise that they are not equipped to deal with this kind of thing properly.
"They need to get a grip and figure it out."
Twitter bosses look set to face questions from MPs when the Culture, Media and Sport Committee examines issues surrounding child protection in the autumn.
Committee chairman John Whittingdale said: "I would have thought it very possible that the committee might want, in the course of our inquiry, to talk to Twitter."
He added: "It isn't that the law needs to be changed; the question is how you identify people and how you prevent them (from abusing others online)."
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 banknote.
This led to the announcement that Jane Austen would feature on the new £10 note from 2017 but also drew her a litany of depraved messages from social networkers.
Ms Creasy was sent similarly vicious tweets when she spoke out in support of the campaigner.
Officers have also questioned and bailed a 21-year-old man in connection with the messages sent to Ms Criado Perez.
Twitter said it was in contact with the police over the abusive tirades.