Despite the claims of some within the Obama administration, al Qaeda and its offshoots aren’t dead, yet. They’ve insinuated themselves into Mali, Somalia, Yemen – and now in Syria, too.

Journalist Jon Lee Anderson of The New Yorker is in Aleppo, which has become a key battleground Syria’s civil war. And in an interview with Christiane Amanpour on Thursday, he gave a unique insight into the fighting there.

Speaking of the out-gunned opposition, Anderson told her, “They’re young men prepared to fight. They believe this is the decisive battle for Syria. That if Bashar al-Assad can’t dislodge them from Aleppo, then it’s over for him. So they have to fight to the death.”

But do they count foreign fighters among their numbers and are there members of al Qaeda and its splinter groups opposing Assad?