A new police unit is being set up across Europe to uncover and block social media accounts being used by Islamic State (IS).

The European police agency Europol will target the estimated 40,000 to 50,000 accounts linked to the terrorist organisation.

Working with unnamed social media companies, it aims to shut down the accounts within two hours of them being discovered.

Calls for more to be done to tackle online radicalisation have mounted in recent weeks after claims that Talha Asmal, who was reported to have become Britain's youngest suicide bomber, was groomed over the internet.

Talha, 17, is alleged to have fled his home in Dewsbury, West Yorkshire, in March to join IS and reportedly detonated a vehicle while fighting for the group in Iraq.

His family said he had been exploited by extremists on the internet "in a process of deliberate and calculated grooming".

Rob Wainright, Europol's director, said the new unit, which comes into force on July 1, would work to identify the key accounts being run in a number of languages that "underpin" what IS is doing and would aim to "identify the ringleaders online".

He told the Guardian it would also monitor social media to identify any activity targeting people who might be vulnerable, as well as those preying on them.

He said: "Who is it reaching out to young people, in particular, by social media, to get them to come, in the first place? It's very difficult because of the dynamic nature of social media."

Mr Wainright added that money used to fund IS would be tracked down, saying: "Where you follow the money trail, it helps find who they are, what they are doing and who their associates are."

Europol believes up to 5,000 people from the EU, including those from the UK, France, Belgium and the Netherlands, have travelled to IS-held areas. Around 700 Britons are thought to have travelled to IS-controlled regions of Syria and Iraq.

The former reviewer of anti-terrorism legislation, Lord Carlile, has called on the Government to work with computer programmers and social media companies to counter extremist propaganda online.