An army chopper has crashed in northwest Pakistan, killing at least 12 people, according to officials.

Pakistani military sources confirmed Thursday evening that the helicopter crashed near Mansehra district in northwestern Khyber Pakhtunkhwa Province, killing all twelve on board.

The aircraft was carrying relief items and aid supplies when it crashed in a hilly region around 170 kilometers (110 miles) north of the capital Islamabad. The helicopter’s main destination was the northern city of Gilgit, where it was supposed to deliver medicine and other aid items.

"All the 12 people in the chopper are presumed dead, they all belong to the army, they were going to Gilgit to rescue an injured army man," a senior military official said, adding, "The dead include army doctors, paramedical staff, the pilots and crew."

Meanwhile, Pakistani Prime Minister Nawaz Sharif voiced deep grief and sorrow over the crash. The premier expressed his condolences to the families of the deceased.

The copter was a Russian-built Mi-17, the same type which crashed in May in hills near Gilgit, killing seven people, including two foreign envoys.

The accident came only hours after a copter belonging to the Pakistani air force crashed during a rescue operation in the flood-hit Chitral region, although no fatalities were reported.

Also on May 8, an army helicopter crashed in Naltar Valley of Gilgit-Baltistan region, killing at least seven people. Ambassador of Philippines Domingo D Lucenario Jr, Ambassador of Norway Leif Larsen and the wives of the Malaysian and Indonesian ambassadors were among seven people killed in deadly aerial crash

A strategically important autonomous region known for its picturesque mountains and natural resources, Gilgit-Baltistan borders China, Afghanistan and Indian-administered Kashmir in northern Pakistan.