A Pakistani airliner carrying 150 people crashed in a ball of flames into densely wooded hills above Islamabad during heavy rain and poor visibility, leaving little hope of survivors.
Rescue officials said pieces of charred flesh and body parts were littered around the smouldering wreckage, partially buried on a remote hillside following Pakistan's first major aviation accident in four years.
Private airline Airblue's flight 202 from Karachi was coming into land at Islamabad's Benazir Bhutto International airport when witnesses saw a jet flying at unusually low altitude before hearing a loud boom.
The plane plummeted in a gorge between two hills, enveloped in cloud and some distance from the road, severely hampering rescue efforts and limiting visibility for helicopters hovering overhead, said an AFP correspondent.
"I saw a big ball of smoke and fire everywhere with big pieces of aircraft rolling down the hill," said police official Haji Taj Gul.
"The plane was flying very low. Then we heard a loud noise," Wajih-ur Rehman, a resident of the smart E-7 neighbourhood in the foothills of the Margalla Hills, told AFP.
Rescue workers have recovered the remains of around 40 people from the wreckage, a city official said.
"We have so far recovered around 40 bodies. They include bodies and parts," Islamabad administration chief Imtiaz Inayat told AFP.
"There are no reports of survivors. Initial reports about five (survivors) have not been confirmed so far," he added.
Rescue official Arshad Javed told AFP: "All we could see were charred hands or feet. I collected two heads, two legs and two hands in a bag.
"There were 150 people on board but no survivor was found. We shouted if anyone was there alive, but heard no voice," he said, returning from the site with four other police and rescue officials.
"The debris of the plane was scattered there in raging fire," Javed said.
"The wreckage of the plane is buried under the debris. First machines have to be deployed there to remove debris of the hill and then we can reach to pull out bodies or survivors -- if any," he told AFP.
Pakistan declared a day of national mourning and called off a cabinet meeting as Prime Minister Yousuf Raza Gilani "expressed grief" over the "tragic incident" and offered prayers for those who had been killed.
Other rescue workers also said there were no apparent signs of survivors, saying that reports from the scene all spoke of body parts.
Anguished families were in tears after hearing of the disaster while waiting at the arrivals terminal where they had intended to meet their relatives.
"We cannot explain our agony, we don't know if he is alive," said Bilal Haider. He said he had come to collect his younger brother Abbas, who went to Karachi for a job interview after getting a Masters in business administration.
"Had we known that this is going to happen, we would never have sent him," Haider told AFP.
Airblue spokesman Raheel Ahmed told AFP the Airbus 321 took off from Karachi bound for Islamabad before 8 a.m. (0300 GMT) with 144 passengers and six crew members on board.
A spokesman for the civil aviation authority said 152 people were on board.
"Apparently the cause of the crash is bad weather, but we leave that to the investigators," Ahmed told AFP.
Ambulances queued along the nearest road and anxious crowds gathered on the approach to the Margalla Hills while dozens of soldiers, paramilitary troops and rescue workers walked painstakingly uphill to reach the site.
Flames and smoke continued to spew from the wreckage hours later.
"It's a big tragedy. It's really a big tragedy," Interior Minister Rehman Malik told Express TV. State television read out the passenger list. No foreigners were believed to be among the dead.
Airblue is one of Pakistan's most respected airlines. It has been operating only since 2004, using new Airbus A320 and A321 aircraft on domestic routes and international services to Dubai, Sharjah, Abu Dhabi, Muscat and Manchester.
Pakistan enjoys a relatively good air safety record.
The most recent fatal commercial crash was a Pakistan International Airlines Fokker F27 that came down in July 2006, killing 45 people on takeoff from the central city of Multan, bound for Lahore.
The deadliest civilian plane crash involving a Pakistani jet was a PIA Airbus A300 that crashed into a cloud-covered hillside on its approach to the Nepalese capital Kathmandu, killing 167 people in September 1992.