This is worrisome. These are NOT nice guys.
Joint military exercises between major but unaligned states …. esp states that have fomented trouble in Iran and Syria, is the kind of activity that led to the wars of the 19th and early 20th centuries. It would be so easy for these guys to make a mistake and start something very bad!
Ask yourself how such a maneuver would affect the new Chinese/Nicaraguan canal or the South China Sea or access to the Artic,