Family members of passengers killed in Wednesday's plane crash wait at a community center today in Islamabad, Pakistan, to give blood to be used for DNA testing to identify their relatives. The Airbus A321 operated by local carrier Airblue crashed into hills during stormy, monsoon weather, killing all 152 people on board.

ISLAMABAD — Relatives desperate to find the bodies of their loved ones joined emergency teams battling thick mud, rain and slippery hillsides today at the scene of Pakistan's worst-ever plane crash.

The Airbus A321 operated by local carrier Airblue crashed into hills overlooking the country's capital, Islamabad, during stormy, monsoon weather, killing all 152 people on board.

The civil aviation authority said the plane had been ordered to take an alternative approach to the runway, but had veered off course. Finding out why will be a key task of the investigation team, said Riazul Haq, director general of the Civil Aviation Authority.

"The fact remains it flew where it should not have done," he said.

Army troops and civilian rescue workers searched a large stretch of the hills scorched by the crash, but the tough conditions slowed the pace of operations. Helicopters could not fly in the heavy rain and low clouds, said a spokesman for the Capital Development Authority, which helps deal with emergencies.

An Associated Press Television News cameraman in the hills saw relatives of passengers working with soldiers and other rescuers at one crash site, where the undercarriage of the jet had come to rest. They had collected several body parts in small bags.

Dozens of relatives and friends of those killed slept outside Islamabad's largest hospital overnight, hoping to receive bodies. They were still there today morning, hugging one another as their tears mixed with the heavy rain, but few corpses were released.

The plane's "black box" flight data recorders have yet to be recovered. Information extracted from them is needed to determine the cause of the crash. Defense Minister Chaudhry Ahmed Mukhtar and other officials have said the government does not suspect terrorism.

The plane was flying from Karachi, the country's commercial capital.

Even when the search is completed, it could take days to identify all the victims with DNA testing since most of the bodies were torn apart and burned in the crash, a grim scene described by rescue workers scouring the twisted metal wreckage.