People gather near the wreckage of a bus plunged into a ravine in Pallandri, Muzaffarabad, on Wednesday. AFP

The accident happened in Pulandri, a district in Azad Kashmir, senior police official Fayyaz Abbasi said. He said several passengers were also injured in the crash and rescuers transported the dead and injured to a nearby hospital.

"The bus carrying up to 40 passengers was going to Rawalpindi when it plunged into a deep ravine while negotiating a sharp turn," local disaster management authority official Raja Moazzam said.

He blamed speeding for the accident and said "authorities are trying to retrieve bodies and injured from the wreckage."

The accident took place in the remote area some 160 kilometres east of Muzaffarabad, the capital of Pakistan-administered Kashmir.

Another local administration official also confirmed the accident and put the toll at 23.

It was not clear what caused the accident and police feared the death toll could rise as some injured were listed in critical condition.

Road accidents are common in mountainous Kashmir and elsewhere in Pakistan and are often blamed on poorly maintained vehicles and highways, and widespread disregards to traffic rules by drivers.