Interpol has urged all countries to obtain biometric data from fighters for the Islamic State and other extremist groups to help law enforcement track them down, especially when they return home.
Interpol Secretary General Jurgen Stock said in an interview with The Associated Press that the international police organisation only has biometric data - fingerprints, DNA, iris scans and the like - for about 10 per cent of the 9,000 foreign terrorist fighters in its database.
Stock said Interpol is helping countries to develop biometric technology not only to identify fighters from extremist groups but criminals as well.
He said there are an estimated 20,000 to 30,000 foreign terrorist fighters from almost all over the world - and about 15,000 from over 100 countries remain mainly in Syria and Iraq.
With 9,000 names in the Interpol database, this means that about 6,000 of the extremist fighters are not on an international register where they could be tracked.
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But Stock said the database has grown rapidly since 2013 when it started with 12 files and will hopefully continue to add names and biometric data.
Stock called the internet a virtual university of terrorism, where extremist groups attract and radicalise would-be fighters, and where information on building or buying bombs and explosives is readily available.
"The threat level with regard to international terrorism is unprecedented," he said.
"We are fighting a terrorist network or an organised crime network with a law enforcement network," he said.
But Stock said it's not easy due to legal issues which differ in various countries including on sharing information and the difficulties in ensuring that relevant data gets to police, border guards and other officials who need it.
