The Bhoja Airlines flight from Karachi with 118 passengers and nine crew members crashed Friday, minutes before it was to land at the Benazir Bhutto International Airport at 7 pm.
The plane had taken off from Karachi at 5 pm. The pilot lost contact with the control tower at 6.40 pm, Geo TV reported. It was the airline's maiden flight on the route.
Gilani termed the crash "a great tragedy in the history of Pakistan". He was speaking to the media after visiting the Pakistan Institute of Medical Sciences (PIMS), where the victims' bodies are kept.
Earlier, officials confirmed that all people on board the plane were dead.
Special counters have been set up at the PIMS to facilitate the relatives, who arrived here Saturday on a special plane from Karachi.
They appealed to the government to complete the investigation at the earliest and make the findings public.
Officials from the National Database and Registration Authority are helping identify the bodies. DNA tests are also being carried, as some of the bodies are mutilated.
Waseem Khawaja, who is in charge of PIMS, said the bodies had been brought in more than 100 bags. At least 100 bodies have been identified so far.
Interior Minister Rehman Malik said today that several officials of the airline, including the owner, have been barred from leaving the country until the probe into the crash is complete.
Meanwhile, US aircraft company Boeing has offered technical assistance in the investigation into the plane crash.
In a condolence message, the company expressed sympathy with the bereaved families and said it was ready to help Pakistan's Civil Aviation Authority in probing the accident.
Aviation sources said the black box flight recorder of the ill-fated plane has been recovered and would help understand the cause of the crash.