Who’s fighting whom in Syria? Explained in 90 seconds

There has been an intense wave of Russian air strikes in two areas of Syria, activists say.

Moscow says it is targeting jihadist groups like Islamic State in co-ordination with Syria's government.

But Nato is worried some of the attacks are hitting rebel groups opposed to President Bashar al-Assad - some of whom are backed by the West.

So just who is fighting whom in Syria?

Jonathan Marcus explains.

Video produced by Mohamed Madi