The helicopter involved in the accident was one of three carrying a delegation of envoys from 37 different countries to inspect projects on a three-day trip to Pakistan's Gilgit-Baltistan territory where they were set to meet with Prime Minister Nawaz Sharif.
Sweden's ambassador, Tomas Rosander, was on the trip, the Swedish Foreign Ministry confirmed to Swedish broadcaster SVT, but was not on board the helicopter that crashed.
"We know that the Swedish ambassador participated in the visit, but he was not in the affected helicopter. The embassy in Islamabad has talked with Tomas Rosander and he is unharmed," Veronica Nordlund a at the Foreign Ministry's press office said.
Leif H. Larsen, the Norwegian envoy, and Domingo D. Lucenario Jr of the Philippines were killed along with the wives of the Malaysian and Indonesian ambassadors, as well as the helicopter's two pilots, according to official tweets by the army.
Polish ambassador Andrzej Ananiczolish and Dutch ambassador Marcel de Vink were also injured, the army added.
The air crash is believed to be the worst in Pakistan since 2012 when a civilian 737 plane went down in Islamabad, killing 130 people.
It is also reminiscent of the 1988 plane crash which killed then military-ruler General Zia-ul-Haq as well as the US ambassador at the time, Arnold Raphel.
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A senior local administration official warned the situation was "urgent" after the helicopter – one of three carrying the delegation, their aides and members of the press – crashed into the school with children inside.
Prime Minister Sharif "expressed deep grief and sorrow" over the incident according to a statement issued by his office, which added that he had been on his way to the region but his plane returned to Islamabad after hearing the news.
The injured were being air lifted to a military hospital in Gilgit, the region's administrative capital, some 50 kilometres to the south-west, a senior local police official told the AFP news agency on Friday.
In the city of Gilgit, a hospital official said injured were being carried on stretchers to the emergency ward of the Combined Military Hospital.
Known for its spectacular mountain ranges and unique culture, Gilgit-Baltistan is a strategically important autonomous region that borders China, Afghanistan and Indian-held Kashmir.