Probably supplied by Turkey. Erdogan is trying to make a new Ottoman Empire. A coupple of days ago he said that he will mobilise the entire islamic world (Sunni) to protect Palestine from Israel. So I would want watch out what he does.
And also, Israel's ally Saudi Arabia. Saudi Arabia often buys weapons from Serbia, signes the end user agreement (meaning the weapons can only be used by the Saudi Arabia), and then they break it and just send those weapons to ISIS.
I used to follow South Front, but they are very anti-Israel, anti-USA, pro-Russia, pro-Iran. And a very biased that way, even extremelly. They are not objective at all.
The same thing is with Russia Today, although I still go there to check what they say regarding Serbia.