Though the Obama Administration continues to refuse to admit it, in launching a war against ISIS in Syria they are on the exact same side of the war as the Assad government. Officials are trying to insist they’ll destroy ISIS and also impose regime change, but in practice, Islamist rebel factions seem to be the only real targets of the war.
Not wanting to admit they’re on Assad’s side, the US is trying to not have anything directly to do with them, which is tough in mid-war. Still, President Bashar Assad says that third parties are conveying a lot of information about the US-led war to them, to keep them informed.
Assad named Iraq as one of the nations providing the general details, though in the past Germany is also said to have done so. He has expressed wishes to coordinate more directly though, saying the information conveyed never gets to the tactical level this way.
This has been a long-standing problem with the US war on ISIS. Before the US launched its war, ISIS was primarily fighting Syria, Iraq, and Iran. The US jumped in nominally to save Iraq, but was desperate to avoid coordinating with Syria and to a lesser extent Iran.
It’s not just about the US not wanting to admit it’s on the same side as Syria, of course. The US has courted Gulf Arab nations like Saudi Arabia and the UAE into the war, and these Sunni nations are on extremely poor terms with Syria and Iran. Trying to sell this as at least sort of a separate war, albeit one that overlaps perfectly with an existing one, was the only way to keep them on board.