Twitter has insisted it has clear processes to help the police tackle racist abuse after former England footballer Stan Collymore was subjected to death threats online.
Collymore, who works as a pundit for radio station Talksport, has asked Staffordshire Police to investigate "horrific" racist tweets.
The former Liverpool, Aston Villa and Nottingham Forest striker claims children as young as ten are being "goaded" by adults into posting racist and sexist tweets.
The 43-year-old star has also accused Twitter of having poor age verification procedures and of "hiding behind" claims that it is unable to comment on individual cases.
In a statement issued via its own site, Twitter told users: "Direct, targeted abuse and specific threats of violence are against our rules.
"You can let us know if you see abusive Tweets by using the new 'Report Tweet' button or through our online forms."
Twitter said its Trust and Safety team, which is being increased in size, worked 24 hours a day to respond to reports of abusive tweets.
Twitter's statement added: "We also have a clear process for working with the police and are in ongoing communication with relevant UK police forces to make sure they are aware of our policies.
"Twitter is an open communications platform. Our priority is that users are able to express themselves, within acceptable limits and, of course, within the law.
"We cannot stop people from saying offensive, hurtful things on the internet or on Twitter.
"But we take action when content is reported to us that breaks our rules or is illegal."
Collymore used his Twitter account yesterday to urge the social media site to do more to combat internet "trolls".
The broadcaster contacted police last night after receiving a spate of racially offensive messages.
Having attracted more than 500,000 followers on Twitter over the past six years, Collymore received the latest in a string of abusive messages after criticising Liverpool striker Luis Suarez following last Saturday's match against Aston Villa.
Appearing as a guest on BBC1's Breakfast programme, the ex-footballer said: "The age user range of Twitter has gone down dramatically.
"I am seeing gangs of kids from ten to 18 goaded by adults to make racist, and homophobic and sexist insults on Twitter, so Twitter need to deal with it.
"It's quite horrific.
"I have no problem with people discussing factual things about me on Twitter.
"If it's illegal I reserve the right as a United Kingdom citizen to live within the laws of the United Kingdom and so should Twitter."
Asked how he had responded to the abusive messages, Collymore said: "I retweet, I report, I block and if it is sufficiently threatening, I will go to the police.
"I have been on it (Twitter) for six years now and it's a fantastic tool to engage in my sport, football, with fans.
"If you disagree with a point that I make it's absolutely fine.
"But I shouldn't be racially abused for it, I shouldn't have somebody that tweets me two days ago saying I am going to turn up at your house and murder you."
A Staffordshire Police spokesman said: "We've been in contact with Mr Collymore to get more information and to reassure him that we will carry out a thorough and detailed investigation.
"Such behaviour is completely unacceptable and we all have a shared responsibility to treat each other with dignity and respect.
"Our investigation into previous alleged offences is continuing and we are currently liaising with Twitter to obtain subscriber details."
Chief inspector Carl Ratcliffe, Staffordshire's lead officer on hate crime, said: "Sadly some people mistakenly believe that anything said or done on Twitter or Facebook somehow doesn't count, they think it doesn't matter because it's not face-to-face.
"They are very wrong. Tweeting abuse is a very personal way of causing distress to someone, and it doesn't matter if the person is famous or not.
"Our investigation in this case is very much ongoing, and involves a number of other police forces, and agencies. We are in regular contact with Mr Collymore, providing ongoing support and keeping him updated."
talkSPORT chief executive Scott Taunton has vowed to "stop promoting" their Twitter accounts in light of the row.
In a statement said: "We are dismayed at the lack of response and perceived inaction by Twitter. Racist or abusive messages of this nature are illegal and unacceptable.
"We have more than three million Twitter followers across our accounts but we will not promote these until we are satisfied that Twitter is doing its utmost to prevent abuse of this nature. We have a duty of care to all our staff and presenters and until I am satisfied that Twitter is treating this seriously we will no longer promote Twitter accounts or use tweets on-air.
"It seems inconceivable that a high-tech company with a market capitalisation of 30 billion dollars appears incapable of preventing racist and abusive tweets being broadcast across its platform."