3 August 2013 Last updated at 05:33 ETColumnist Grace Dent received a bomb threat on Twitter
Social networking site Twitter has issued new rules to help clamp down on abusive behaviour.
The company said it had updated its rules to make it clear that abuse will not be tolerated.
Extra staff have also been put in place to handle reports of abuse, Twitter said.
The move comes after police revealed they were investigating allegations by eight people of abuse or threatening behaviour on the site.
Scotland Yard said its e-crime unit was looking into the claims, three of which involve incidents outside London.
Three female journalists said they had been the subject of bomb threats on the site, while an MP and a campaigner received threats of rape.
The revelations sparked a backlash online, with a petition calling for Twitter to add a "report abuse" button to tweets attracting more than 120,000 signatures.
'Clear message'In a message posted on its blog, Twitter's senior director for trust and safety, Del Harvey, and UK general manager Tony Wang, said the company had updated its rules in light of feedback from customers.
They said: "It comes down to this: people deserve to feel safe on Twitter."
The company has clarified its guidance on abuse and spam - reiterating that users "may not engage in targeted abuse or harassment".
And from next month an in-Tweet "report abuse" button already available on some mobile devices will be rolled out across the main Twitter website and apps.
Ms Harvey and Mr Wang wrote in their blog: "We want people to feel safe on Twitter, and we want the Twitter rules to send a clear message to anyone who thought that such behaviour was, or could ever be, acceptable."
They said additional staff were being added to the teams that handle abuse reports and the company was working with the UK Safer Internet Centre, which promotes the safe and responsible use of technology.
"We are committed to making Twitter a safe place for our users," they said, adding: "We're here, and we're listening to you."