Islamist fighters carry their flag during a funeral outside Aleppo, Syria.

More than 6,000 new fighters in Syria joined the Islamic State in Iraq and Syria (ISIS) last month in the militant group’s fastest expansion to date, a body monitoring the war said on Tuesday.

ISIS, previously estimated to number some 15,000, has seized control of large areas of Syria and Iraq.

Just over a thousand of the new recruits are foreign and the rest Syrian, Rami Abdelrahman, founder of the Syrian Observatory for Human Rights, told Reuters.

The organization says it gathers data from all sides of the Syrian conflict.

 
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