The Mi-17 helicopter of the army's aviation wing was returning from a sortie to the Gyari sector of Siachen when it caught fire and crashed near the airport in Skardu town, police said.
Three personnel on board the helicopter were killed and two others were injured, police officials were quoted as saying by TV news channels.
It could not immediately be ascertained if the accident had resulted in any damage on the ground.
The army's aviation wing has a base at Skardu, one of the main towns of the Gilgit-Baltistsan region.