BEIRUT - Between 3,300 and 11,000 fighters from more than 70 nations, including a rising number from Western Europe, have joined the struggle in Syria against President Bashar Assad, a research group reported on Tuesday.
After security forces repressed peaceful protests against more than 40 years of Assad family rule in 2011, an armed revolt ensued with an increasingly sectarian element. Well over 100,000 people have been killed and millions forced from their homes.
"We estimate that - from late 2011 to 10 December 2013 - between 3,300 and 11,000 individuals have gone to Syria to fight against the Assad government," said the International Centre for the Study of Radicalization (ICSR), a partnership of five universities based at King's College London.
"These figures include those who are currently present (in Syria) as well as those who have since returned home, been arrested or killed."
The ICSR said it used 1,500 sources, including media reports, government estimates, jihadi statements and social media to collect the data.