Almost every report I have heard, from the media and from people directly there, has made it clear that these are mixed-race groups of young people.

This is not 'immigrant communities', this is people who were born here.

Source required. It's not completely clear what you mean by native and immigrant, but it could be construed as racial slander. Please clarify and source.

NB - I'm not normally a stickler for sourcing, but I feel a statement as controversial as this requires one.

I disagree that we are seeing any significant number of first generation immigrants here.

I think by immigrant communities he was also including immigrants children (1st 2nd generation or more). I've seen this used as to visible minorities in many places around the world. Including country that are mostly immigrants like Canada (where I'm from).

What has been reported is that it's youth from poor neighborhoods. Considering the population composition of those neighborhoods, I'm going to guess that it's probable the groups are composed of a majority of people from those immigrant communities. It still doesn't mean it's a immigrant riot. I bet poor non-immigrant (as in their family always been there) are also participating.

Everyone in Canada is an immigrant of some type - unless you are native

Everyone everywhere except maybe in Africa is an immigrant of some type. At some point we just stop calling them immigrants, though.

I've seen plenty of perfectly white skin in the crowds, though not necessarily on their faces, of course.