Pakistan says the foreign diplomats were flying in a military helicopter which crashed into a school © AFP/File Banaras Khan Naltar (Pakistan) (AFP) - At least four people were killed Friday, including two pilots and two or three foreigners, when a helicopter crashed on a school in northern Pakistan, the army said, warning that casualties could rise.

"Update Naltar: Info so far; two pilots and two-three foreigners fatalities. Thirteen survivors with varying degree of injuries," tweeted Asim Bajwa, Pakistan's army spokesman.

The helicopter was one of three taking a delegation of foreign diplomats and their aides to Pakistan's Gilgit-Baltistan territory, which is part of the disputed Kashmir region.

The ambassadors of Norway and the Philippines were among those killed. The helicopter crashed into a school in northern Pakistan, the army said in a tweet.

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.