The head of Nato has told ITV News the alliance must "face the reality" that it will have to strike "out of area" at some points to ensure its members' security.
Secretary General Anders Fogh Rasmussen told International Affairs Editor Rageh Omaar that Nato would "take all steps necessary" to ensure protective defence and protection of our allies".
He was discussing the threat of Islamic State militants and the creation of a planned "high-readiness force", which will deal with threats posed by local threats such as Russian aggression, as well as more distant ones.
In particular he said the international community has an "obligation to stop the advance of the so-called Islamic State".
I've been told at the Nato summit that the intelligence services know exactly who 'Jihadi John' is - or at least are 99.9% certain.
The British aid worker being held by Islamic State is David Haines, a 44-year-old father-of-two from Perth, Scotland.
In a video statement which claims to record his final words US hostage and journalist Steven Sotloff blames US foreign policy for his death.