Islamabad: Pakistan observed a day of mourning on Thursday for the 152 people killed in its worst aviation disaster, as a monsoon deluge delayed the search for the aircraft`s black box in hilly woodland.
The Airblue passenger jet from Karachi crashed in a ball of flames, killing everyone on board and disintegrating in the heavily-forested Margalla Hills outside the Pakistani capital in heavy rain and poor visibility.
Pakistani flags were flying at half mast from all public buildings in mourning for the dead. Businesses took out advertisements in the national press to honour colleagues who were killed or to express condolences.
"Rescue teams will resume the search operation as soon as it stops raining as we still have to find the black box," police official Bani Amin said.
Investigators hope the flight data recorder will give clues to the fate of the 10-year-old Airbus, which was piloted by an experienced captain.
Two Americans, an Austrian-born businessman, five children and two babies were among the 152 people on board flight ED 202.
The Airbus 321 was coming in to land at Islamabad`s Benazir Bhutto International airport on Wednesday when witnesses saw it flying at an unusually low altitude before hearing a deafening boom.
The plane broke apart into a gorge between two hills, scattering debris across hillsides enveloped in cloud and some distance from the road, severely hampering initial rescue efforts.
The government said all possible causes would be investigated, including terrorism, bad weather and sabotage, although officials gave no indication that an attack might have been to blame.
It was the worst aviation tragedy on Pakistani soil in history, piling more woes onto a country on the frontline of the war on al Qaeda, where Islamist militant bombers have killed more than 3,570 people in the past three years.
US President Barack Obama offered his "deepest condolences" over the plane crash. UN chief Ban Ki-moon said he was "deeply saddened" and China`s President Hu Jintao also conveyed his condolences.
Many of the victims were charred beyond recognition or ripped to pieces, forcing health officials to use DNA tests to identify them, which could lead to an agonising wait.
Information Minister Qamar Zaman Kaira told reporters that the remains of 115 bodies had been recovered and that it could take up to a week to identify the most charred remains, urging relatives to exercise patience.
Rescuers held out hope on Thursday that more remains could be picked off the hillside, despite the inferno of the crash.
"It is a tragedy, a great tragedy. The cause of the crash is a technical issue and anything said about the cause at this time is speculation. Every thing will be clear after the inquiry," Kaira said.
Zamurad Khan, head of state-run charity Baitul Maal, said at the Pakistan Institute of Medical Sciences that 63 bodies had been handed over to relatives with the others held back in the morgue for identification.
Authorities have set up an office to collect DNA samples from relatives in order to identify remains.
Attentions focused on Thursday on why the pilot was flying the jet so low and close to the Margalla Hills -- off the normal route for aircraft trying to come into land in Islamabad even during monsoon rains.
Airblue, one of Pakistan`s most respected airlines, was tight-lipped about any possible technical or pilot error.
Reports said the pilot was told by air traffic control to take another route, but company spokesman Raheel Ahmad said that this was mere speculation.
Airblue expects a team to arrive from Europe`s Airbus to assist with inquiries, and records about the aircraft and passengers have been submitted to Pakistan`s Civil Aviation Authority, he said.
The only deadlier civilian plane crash involving a Pakistani jet saw a PIA Airbus A300 crash into a cloud-covered hillside on approach to the Napalese capital Kathmandu in 1992, killing 167 people.