Foreign fighters are streaming into Syria at a rate of roughly 1,000 a month, with no let-up in the flow despite international efforts to stem the tide, US officials said today.
The surge in foreign militants heading to Syria surpasses anything seen in previous conflicts in the past 10 years, including wars in Afghanistan, Yemen, Somalia or elsewhere, said a US intelligence official, who spoke on condition of anonymity.
"It's safe to say this conflict stands out with the highest rate in the last decade," the official told AFP.
US intelligence agencies now believe there are more than 16,000 volunteers from 80 countries that have travelled to Syria to fight with various militant groups, including the Islamic State jihadists who have seized large swathes of territory in Iraq and Syria.
"All of these numbers are trending upward," the official said.
There was no sign yet that US-led air strikes against the Islamic State group in Syria and Iraq or new restrictions aimed at foreign volunteers in several countries had affected the flow, officials said.
Analysts say the numbers may be much higher while US officials acknowledge that tracking the movement of foreign volunteers remains a challenge and that any figure released is only a rough estimate.
"We have limited insights on this," the official added.
Most of the volunteers have come from the Middle East and North Africa, with the highest number of fighters flowing out of Tunisia, officials said.
More than 2,000 hail from European nations and more than 100 from the United States, with a small number, about a dozen -- linked to the Islamic State group, according US estimates.
The numbers on foreign fighters were first reported by NBC News and the Washington Post.
