The European Union and US Internet giants including Facebook and Twitter will work together to combat online extremism and have discussed steps to block gruesome beheading videos, officials said Thursday.

EU interior ministers and officials met representatives from the technology firms in Luxembourg on Wednesday amid growing alarm that Islamist material is encouraging young Muslims to fight in Syria and Iraq.

EU home affairs commissioner Cecilia Malmstroem said Google, Facebook, Twitter and Microsoft had explained what they do to prevent showing the videos, "which according to their internal policies are totally against their principles".

But the Swede insisted that outright blocking of websites "is not the question".

She added: "There is urgency, but we should not rush into making laws or taking decisions without thinking."

In a later joint statement, Malmstroem and Italian Interior Minister Angelino Alfano said the two sides "agreed to organise joint training and awareness-raising workshops for the representatives of the law enforcement authorities, Internet industry and civil society".

Extremists using web to recruit

Social media has become a powerful recruiting tool for jihadists, with the Islamic State group posting several videos online showing the grisly beheadings of Western hostages.

US Internet firms have sometimes been uneasy about blocking extremist material, seeing themselves as platforms rather than publications, and worrying about the implications for free speech, which is strongly protected under US law.

EU counter-terrorism coordinator Gilles de Kerchove, who was also at the dinner, said the US firms were "very eager to do their part" in what he called a joint public-private effort to combat extremism.

They discussed "how can we remove from the Internet illegal content, how can we use it proactively in order to counter their narrative," he said.

"Twitter has made the life of ISIL (Islamic State) quite difficult. That's the reason why they moved from Twitter to another social network," he added.

Around 3,000 Europeans have travelled to fight in Syria and Iraq, de Kerchove told AFP in September.

Officials worry some will return battle-hardened and ready to launch attacks in their home countries.

Many European parents have learned that their sons or daughters have left to fight or support jihad in Syria through messages posted on Facebook or Twitter.

Police officers who are worried that they might return to launch attacks in their home countries need such messages to determine where they are, a European official said.

The aim of cooperating with the social networks is to block the broadcast of messages and images of jihadist groups, something that must be done rapidly as the documents are duplicated quickly.

Facebook, the world's biggest social network with 1.3 billion user accounts, said it has barred "terrorist" groups from its site.

The firm intervenes when it becomes aware of accounts or content that violate user conditions, particularly in cases of calls to violence, according to Monika Bickert, Facebook head of global policy management.

The ministers were also looking into how to reinforce border checks to prevent jihadists leaving for the Middle East, and monitoring the return of those who might be preparing attacks.

However, the Schengen border-free zone, which applies to most EU countries, bars systematic checks, and the European parliament has blocked plans for a European Passenger Name Record system, a database that holds the itinerary of airline passengers.