We must close loopholes exploited by foreign fighters, says Interpol chief
Dangerous gaps in screening for terrorists must be addressed as efforts to counter the threat stand at a "critical stage", a crime-fighting chief has warned.
Greater co-ordination is needed in the response to foreign fighters returning from conflict zones, according to Interpol secretary general Jurgen Stock.
Increased military pressure on Islamic State - also known as Isil - including the offensive in Mosul, has sparked concern about potential displacement of militants.
Attending a meeting of interior ministers in Rome, Mr Stock said estimates place up to 15,000 fighters still within conflict zones.
He said: "The concern is what these foreign terrorist fighters will do with the skills acquired in battle and the networks which facilitated their recruitment when they leave the conflict zones.
"We are moving away from the original Isil foreign terrorist fighter landscape, with flows now potentially heading towards multiple conflict zones as well as individuals returning to their countries of origin."
He said foreign terrorist fighters of more than 80 nationalities have been reported to the agency.
Mr Stock added: "We stand at a critical stage in our efforts against the terrorist threat.
"International action can and will bring concrete results, but we must be systematic and consistent.
"We must close the loopholes being exploited by terrorists at the national, regional and international levels if we are to succeed."
It was revealed earlier this year that around 850 people linked to the UK and regarded as a security threat are believed to have taken part in the Syrian conflict, with just under half thought to have returned to the country.
The threat from international terrorism in the UK currently stands at severe, indicating that an attack is "highly likely".