The Pakistani Taliban Friday claimed responsibility for downing a military helicopter, killing six people including the Norwegian and Philippine envoys, and said Prime Minister Nawaz Sharif was their target.

"The helicopter was shot down by an anti-aircraft missile, killing pilots and many foreign ambassadors," an Urdu-language statement emailed by their main spokesman Muhammad Khorasani said.

It was not immediately possible to verify the claim, but the Gilgit-Baltistan region in Pakistan's north where the chopper came down is not known as a stronghold for the militant organisation.

An earlier statement by Sharif's office had said his plane was en route to the Gilgit area at the time of the attack but turned back to Islamabad after news of the crash broke.