Are ISIS's "external operations" under way?

Another ominous comment from McCaul, which one wonders is based upon intelligence reports or speculation: “Their focus right now is establishing the caliphate. But don’t kid yourself for a second, they are [sic] intent on hitting the West. And there are external operations, I believe, under way…We have tens of thousands of foreign fighters from all over the world pouring into this safe haven that’s now been established, including hundreds of Americans with Western passports and legal travel documents, which would enable them not only to travel to Western Europe, but to the United States.”