EU foreign affairs head Federica Mogherini said Monday Russian intervention in Syria was a "game-changer" and called for coordination to avoid "extremely dangerous" risk.

"It is for sure a game-changer, it has some very worrying elements... it has to be coordinated otherwise it risks being extremely dangerous, not only from a political point of view but also military," Mogherini said as she arrived for an EU foreign ministers meeting dominated by the Syrian crisis.