The killer quake leveled villages east of Algiers late Wednesday, leaving at least 1,467 people dead and 7,207 injured, according to the Algerian Interior Ministry. Many thousands more people were homeless.
Officials said the death toll would only mount as bodies were pulled from buildings leveled by Wednesday's temblor.
"Unfortunately we have not finished establishing these increasingly tragic figures," Algerian Prime Minister Ahmed Ouyahia told reporters in the quake zone. "What is worrying is that there are still many under the rubble."
Thousands of people fled their homes, complaining of shoddy construction and the fear that buildings still standing could soon collapse. Police erected roadblocks and stepped up patrols near the capital, Algiers, to prevent looting.
Entire families are among the dead. The 6.8-magnitude quake crumbled apartment houses, knocked down walls and flattened mosques. The injured clogged hospitals. Countless bodies were trapped under the wreckage.
"There is nothing left," shouted one woman, grief-stricken in the aftermath of the quake. "We came from God and unto God we return."
Rescue workers are encountering both despair and hope as they continue their increasingly difficult work.
CBS News Correspondent Allen Pizzey reports one group of rescuers called out through a hole in a collapsed floor, to see if anyone might be trapped below. A woman answered - but said that she could not hold on - her two sons, who were with her, were already dead.
There was also a moment of joy when two young boys were pulled alive from the devastation. "Don't cry,"the firemen told them. "You're safe now."
A journalist from France-Info radio in the Boumerdes district east of Algiers reported that rescue workers from the Mediterranean port city of Marseille, France, found a survivor - a young woman.
Emergency squads also located four people trapped under the debris, two of them young girls who spoke to rescuers, the report said. Rescuers believe they can pull the four out of the debris.
The quake hit about 7:45 p.m. Wednesday, with its epicenter east of Algiers. It was the North African nation's deadliest since a pair of temblors west of the capital killed up to 5,000 in October 1980, according to the U.S. Geological Survey.
In the downtrodden Bab El Oued neighborhood, one of the worst hit in the capital, thousands of people slept in the streets out of fear that aftershocks could bring down unstable apartment buildings. Makeshift tents were set up in parks for women and children.
Balconies had tumbled to the ground and stairwells collapsed on top of one another, but the apartment buildings remained standing in the neighborhood.
"It was a close call," Sadek Bouraoui, a customs officer, said of his Bab El Oued home. "Living here risks the lives of my wife and children, but we have nowhere else to go," said Bouraoui, 32, who brought a mattress from his apartment into the street.
Closer to the epicenter, in Roubia, 13 miles east of the capital, the cries of women mingled with the wail of ambulance sirens. An AP reporter saw blocks of buildings in ruins, with unknown numbers of bodies trapped underneath.
Rescue services were overwhelmed. Women cried the names of their dead or injured children. Bodies were piled at the town morgue, wrapped in blankets or plastic bags. Machines lifted away rubble.
"The building shook like a ship. I sheltered with my daughters in a doorframe. That's why we're still alive," said Fatma Ferhani, 70.
Hospitals overflowed with the injured and some were even treated in the streets for fear of more aftershocks.
Foreign aid groups and governments sprang into action, rushing over rescue workers, doctors and dogs to search for survivors. Food, blankets and medicine for the shocked, injured and homeless were on their way.
In Algiers, electricity was cut in some neighborhoods and some phone lines were downed. The loss of power and scores of aftershocks that rocked the area in the hours after the quake caused panic.
The capital, however, was mostly spared from the devastation further east.
A four-story hotel frequently used by athletes was severely damaged, killing the Romanian head of Algeria's track and field team and the Bulgarian-born coach of the national weightlifting squad.
Shocks were felt into the Mediterranean. The quake triggered 7-foot waves in Spain's Balearic islands, 175 miles north of Algiers, that damaged or destroyed 150 boats, officials said.
The temblor also ruptured underwater cables, cutting phone links to Algeria and seriously disrupting international communications with countries in Asia, the Middle East and the Pacific, France Telecom said.
For Algeria, the quake carried risks of political aftershocks, too.
The government has been battling Islamic insurgents for more than a decade and, with elections due next year, support for President Abdelaziz Bouteflika could slide if efforts to help quake survivors flag.
Muslim fundamentalists have traditionally excelled in helping the needy. To oversee rescue efforts, Bouteflika canceled plans to join a summit of world leaders in France next week, APS reported.
Many Algerians have complained about the wobbly state of buildings and a housing shortage in the oil-rich country. In a suburb of the capital, residents have said it is not uncommon for three families - roughly 14 people - to cram into a three-bedroom apartment; others sleep in hallways each night.
The U.S. Geological Survey, which monitors quakes around the world, said the temblor had a preliminary magnitude of 6.8.
Towns throughout Boumerdes were devastated, with many buildings tilted drunkenly. Residents swarmed to area hospitals, with injuries or to seek news of loved ones. Dozens of bodies were laid out, wept over by families.
In Dergane, near the epicenter, eight members of the same family - including a month-old baby - were killed as they sought shelter in their cellar.
Authorities called for blood donors, and medical personnel and employees of Sonelgaz, the state company that supplies electricity, were asked to help.
Messages of sympathy and help poured in from around the world.
"Our prayers are for the victims, their families, and the entire Algerian nation. The United States stands ready to help," said President Bush.
France, Algeria's former ruler, dispatched two rescue teams of 60 members each and President Jacques Chirac sent condolences. Germany sent a team of 22 quake specialists and 10 search dogs. The European Union said it also was coordinating disaster relief efforts with Belgium, Italy, Spain and Greece, which all sent or were sending rescuers and medical staff. Egypt flew over 13 tons of food, medicine, blankets and tents.
Hundreds of Algerian Red Crescent staff and volunteers treated the injured, transported them to hospitals and mobilized blood donors.
Authorities said they feared that the earthquake has damaged water and sanitation facilities.