A Pakistani passenger plane carrying 160 people on Wednesday crashed into the heavily forested Margalla Hills overlooking Islamabad due to bad weather. Many passengers were feared killed in the mishap.

Private airliner Air Blue operated Airbus A-321, flying from Turkey to Islamabad via Karachi, hit the Margalla Hills near Daman-e-Koh viewpoint at approximately 10 am in thick fog, said the police.

The police said bodies of the passengers were strewn across the low mountains near the scene of the smouldering wreckage in inaccessible hills, shrouded in heavy cloud and fog during a downpour.

"Rescue teams, paramilitary Pakistan Rangers and senior police officials have reached the site. The weather is unfriendly but still some helicopters reached the site and airlifted five survivors to the hospital," Malik said.

Rescue workers had to trek for over an hour to reach the site. "They have been directed to remove any survivors on stretchers," Malik said.

"We have sought helicopters from the army's aviation wing and a counter-terrorism body. We will need at least eight to 10 helicopters because of the inaccessibility of the area," she said.

Sources in the Civil Aviation Authority expressed surprise at authorities clearing the aircraft to land at Islamabad despite the poor visibility and bad weather around the federal capital. The sources told PTI that state-run Pakistan International Airlines had diverted all its flights to Islamabad to Lahore.

Footage aired on TV news channels showed thick white smoke rising from the crash site. Witnesses said they had seen flames in the wreckage of the aircraft.

Authorities declared an emergency in all hospitals in Islamabad. Scores of anxious relatives of passengers gathered at the Benazir Bhutto International Airport to get information about their kin.

President Asif Ali Zardari and Prime Minister Yousuf Raza Gilani expressed shock and grief at the crash and directed authorities to take coordinated measures to reach the inaccessible site.