NEW YORK: About 30,000 foreign fighters, including 250 Americans, have travelled to Iraq and Syria since 2011 with most of them looking to join the dreaded Islamic State terror group, according to a media report.
There has been a doubling of volunteers in just the past 12 months which gives stark evidence that an international effort to tighten borders, share intelligence and enforce anti-terrorism laws is not diminishing the ranks of new militant fighters, the New York Times reported.
Among those who have entered or tried to enter the conflict in Iraq or Syria are more than 250 Americans, up from about 100 a year ago, the report said citing intelligence and law enforcement officials.
American intelligence analysts have been preparing a confidential assessment that concludes that nearly 30,000 foreign fighters have travelled to Iraq and Syria from more than 100 countries since 2011, the report said.
A year ago, the same officials estimated that flow to be about 15,000 combatants from 80 countries, mostly to join the Islamic State.
That grim appraisal coincides with the scheduled release on Tuesday of a six-month, bipartisan congressional investigation into terrorist and foreign fighter travel, which concludes that "despite concerted efforts to stem the flow" the US has largely failed to stop Americans from travelling overseas to join jihadists.
The focus on shortcomings in the global effort to combat the Islamic State, also known as ISIS, is playing out as tens of thousands of refugees flee strife in the Middle East and North Africa, including many seeking to escape the violence in Syria and oppression in areas under the control of the terror group.
Despite Pentagon reports that coalition strikes have killed about 10,000 Islamic State fighters, the group continues to replenish its ranks, drawing an average of about 1,000 fighters a month, the report said.
The government several months ago last publicly assessed the flow at "more than 25,000", including at least 4,500 from the West. Given the region's porous borders, American officials emphasise that their figures are rough estimates not precise head counts, based on allies' reports on citizens' travel and other intelligence, which vary by country.
In Britain, more than 750 people have travelled to take part in terrorist-related activity in Syria and Iraq, up from about 500 a year ago. About half of those have returned home, raising fears that they could carry out attacks on British soil.