Military aircraft that conducted air strikes against ISIS military targets in western Iraq are believed to have been from Syria’s air force, a U.S. official told ABC News.
Such air strikes would be a regional escalation of the conflict inside Iraq where the Islamic militants have taken over cities in northern and western Iraq and threatened the stability of the Iraqi government.
http://abcnews.go.com/blogs/politics/2014/06/syrian-war-planes-strike-isis-targets-in-iraq-us-says/