Prime Minister Nawaz Sharif was travelling to the mountainous northern region of Gilgit on a separate aircraft to launch two projects when the accident happened. He returned to Islamabad, his office said.
Military spokesman Asim Bajwa said in a Twitter post that as well as the four foreigners, the two pilots were killed.
He said the ambassadors of Poland and the Netherlands were among the injured.
Reuters reported said 11 foreigners and six Pakistanis were on board the MI-17, which crashed into a school Gilgit and caught fire.
Editor: Priyambodo RH
Copyright © ANTARA 2015