JAKARTA (AFP) - An Indonesian ambassador who was on a Pakistani military helicopter that crashed this month killing two other foreign envoys died on Tuesday after battling severe burn injuries, Indonesia's foreign minister said.

Ambassador Burhan Muhammad, 58, was aboard the military helicopter, along with his wife and a delegation of ambassadors when it crashed on May 8 and set a school building ablaze in the Gilgit area of northern Pakistan.

His wife, the Norwegian and Filipino ambassadors, and the wife of the Malaysian envoy were killed immediately.

Mr Muhammad had severe injuries and had to be evacuated to the Singapore General Hospital last week. "Indonesia's foreign ministry has just lost one of its best diplomats, Ambassador Burhan Muhammad, who passed away at 12.50am on May 19 local time in Singapore," Foreign Minister Retno Marsudi said.

Mr Muhammad and his wife are survived by their two sons.

The Pakistani Taleban claimed to have struck the aircraft with a ground-to-air missile hoping to assassinate Prime Minister Nawaz Sharif who was flying to the region at the same time - but the claim was rebutted by officials and multiple eyewitnesses, including foreign secretary Aizaz Ahmad Chaudhry.

The military and Pakistan's foreign office said the crash was due to a technical fault while landing. Officials added the school was shut at the time.

It was Pakistan's worst air crash since 2012, when a Boeing 737 passenger plane went down in Islamabad, killing 130 people.