Norwegian envoy Leif H Larsen, Philippines ambassador Domingo D Lucenario Jr, wives of Malaysian and Indonesian ambassadors and two pilots were killed in the incident while Polish ambassador Andrzej Ananiczolish and Dutch ambassador Marcel de Vink sustained injuries.
The delegation was on its way to inspect projects on a three day trip to Gilgit-Baltistan where they were set to meet with Prime Minister Nawaz Sharif.
The military and Foreign Office said the crash was due to a technical fault while landing.
A statement by the PM office said Nawaz was on a plane en route to the Gilgit area at the time of the incident, but turned back to Islamabad after news of the crash broke.
The prime minister was due to inaugurate a chair-lift at a ski resort. The premier "expressed deep grief and sorrow" and announced a day of mourning, according to his office.