At least eight boulders, some the size of a small house, fell from the towering Muqattam cliffs outside Cairo and buried about 50 homes in the village of Manshiyet Nasr, one of many densely populated slums ringing Africa's most populous city.
The official said 35 people were injured and, according to residents, there could be up to 500 people buried under the hundreds of tons of rock that fell. He spoke on condition of anonymity because he was not authorized to speak to the press.
"My whole family is underneath the rock," sobbed Anwar Ragab by phone to the Associated Press as he watched a body being pulled from under the rock. "I don't know what to do, I can't do anything - I just want my children back."
The town was covered by a thick layer of dust and the scene was chaotic as men and women screamed in grief. People tried to lift the massive rocks by hand, calling out the names of relatives and family members stuck under the debris.
Police using search and rescue dogs probed the rubble, but six hours after the disaster, there was no sign of heavy machinery to assist in clearing the rock.
Angry residents yelled at police and government officials at the site, blaming them for the tragedy.
The government issued a statement saying survivors would be transferred to new housing for the night and given all necessary aid.
"We are following the case step by step and providing the care and comfort for the residents," Prime Minister Ahmed Nazif said in the statement. "We would like to remind people the danger of building informal housing in dangerous areas."
The boulders came crashing down at 7 a.m., when most residents were still sleeping after waking earlier to eat ahead of the daytime fast of Islam's holy month of Ramadan.
"I couldn't find my house this morning," said Mustafa Abdel-Fatah, who spent the night at a friend's house in a different neighborhood. "I could only see rocks on top of everything."
Haidar Baghdadi, the parliamentarian for the region, told Al-Jazeera news channel that buried residents were calling for help from under the rubble using cell phones.
The deputy added that the area was known to be dangerous and the residents were supposed to be resettled to government housing. He also criticized the lack of government emergency response.
"We should have removed these rocks five years ago to protect the people underneath or moved the people," he said, blaming the Housing Ministry for the disaster.
Rock slides periodically take place on the edges of the brittle Muqattam hills outside Cairo. The base of the cliffs are home to dozens of slums built by impoverished migrants from the countryside looking for work in the city.
In 1994, some 30 people were killed in another rock slide in the same area.