brussels european union friday say u.s. missile strike syrian airbase understandable intention prevent chemical attack stress negotiate solution way conflict us inform european union ... launch strike shayrat airfield syria understandable intention prevent deter spread use deadly chemical weapons eu top diplomat federica mogherini say behalf bloc 28 member state us also inform us strike limit focus prevent deter use chemical weapons atrocities ... find responsible sanction within framework unite nations eu say understand aim u.s. strike syria