The death toll in the worst Guatemala earthquake since 1976 rose Thursday to 52 people, with many of the 22 still missing expected to be among the dead, according to President Otto Perez Molina.

Perez said the powerful 7.4-magnitude quake that hit Wednesday morning off the Pacific coast affected as many as 1.2 million people as it shook nearly the entire country. He said a little more than 700 people were in shelters, with most opting to stay with family or friends.

"They have no drinking water, no electricity, no communication and are in danger of experiencing more aftershocks," Perez told a news conference. The president said there had been 70 aftershocks in the first 24 hours after the quake, some as strong as magnitude 4.9.

Damaged homes will be among the biggest problems the country will face in the coming days, Perez added.

Guatemalans fearing aftershocks huddled in the streets of the mountain town of San Marcos, the most affected area, where at least 40 people died. Others crowded inside its hospital, the only building left with electricity. More than 90 rescue workers continued to dig with backhoes at a half-ton mound of sand at a quarry trying to rescue seven people.

"We started rescue work very early," said Julio Cesar Fuentes of the municipal fire department. "The objective is our hope to find people who were buried."

Relatives of Cruz Abel De Leon react when his body was found in a landslide triggered by a 7.4-magnitude earthquake, in El Recreo, in the outskirts of San Pedro Sacatepequez, in the San Marcos region, about 250 km (155 miles) south of Guatemala City, November 8, 2012. A strong earthquake off the coast of Guatemala killed at least 48 people and trapped others under rubble on Wednesday, crushing homes and cars, destroying roads and forcing evacuations as far away as Mexico City. REUTERS/Jorge Dan Lopez

But they uncovered only one more body, that of one of the quarry workers. The worker's son was called to identify him.

When he climbed into the sand pit and recognized the clothing, the man collapsed onto the shoulders of firefighters, crying: "Papa, Papa, Papa." He and his father were not identified to the news media because other relatives had not been notified of the death.

Residents venturing outside into the morning cold found the city paralyzed and businesses closed.

In the town of San Cristobal Cochu, firefighters picked at a collapsed house trying to dig out 10 members of one family, including a 4-year-old child, who were buried, fire department spokesman Ovidio Perez told the radio station Emisoras Unidas.

Volunteers carrying boxes of medical supplies began arriving in the area in western Guatemala late Wednesday.

Eblin Cifuentes, a 26-year-old law student, and a group of his classmates already were collecting medical supplies as part of a school drive to provide aid for the only hospital in San Marcos, a poor, mainly indigenous mountain area of subsistence farms. When the quake hit, the group decided to bring everything they had collected.

"Thank God nothing happened to us and that's why we have to help out," Cifuentes said.

Damage reported as far as Mexico City

The quake caused terror over an unusually wide area, with damage reported in all but one of Guatemala's 22 states and shaking felt as far away as Mexico City, 965 kilometres to the northwest.

It hit hardest in San Marcos, where more than 30 homes collapsed and many of the colorful adobe buildings in its centre were either cracked or reduced to rubble, including the police station and the courthouse. The temblor tore a large gash in one of the streets. Hundreds of frightened townspeople stayed in the open, refusing to go back inside after more than five strong aftershocks shook the area.

'We asked the president to improve conditions at the hospital. There isn't enough staff.'—Ingrid Lopez, relative of earthquake victim

President Otto Perez Molina said that 40 people died in the state of San Marcos and eight more were killed in the neighbouring state of Quetzaltenango.

Hundreds of people crammed into the hallways of San Marcos' small hospital after the quake seeking help for injured family members. Some complained they were not getting care quickly enough.

Ingrid Lopez, who bought in a 72-year-old aunt whose legs were crushed by a falling wall, said she had waited hours for an X-ray.

"We ask the president to improve conditions at the hospital," she said. "There isn't enough staff."

People believed buried alive

More than 300 firefighters, policemen and civilians dug desperately at a half-ton mound of sand at a quarry trying to rescue seven people believed buried alive. Among those under the sand was a 6-year-old boy who had accompanied his grandfather to work.

"I want to see Giovanni! I want to see Giovanni!" the boy's mother, 42-year-old Francisca Ramirez, frantically cried. "He's not dead. Get him out."

Residents on motorcycles drive past a damaged road after the earthquake struck in San Marcos, Guatemala, on Wednesday. (Moises Castillo/Associated Press)

By Wednesday night, firefighters had dug out two bodies from the quarry, including Giovanni's.

The president flew to San Marcos to view the damage in this lush mountainous region of 50,000 indigenous farmers and ranchers, many belonging to the Mam ethnic group.

"One thing is to hear about what happened and another thing entirely is to see it," the president told The Associated Press. "As a Guatemalan I feel sad … to see mothers crying for their lost children."

The president said the government would pay for the funerals of all victims in the impoverished region.

The quake, which was 32 kilometres deep, was centred 24 kilometres off the coastal town of Champerico and 161 kilometres southwest of Guatemala City. It was the strongest earthquake to hit Guatemala since a 1976 temblor that killed 23,000.

'As a Guatemalan I feel sad … to see mothers crying for their lost children.' —Guatemalan president Otto Perez Molina

Officials said most of 100 missing were from San Marcos, where people farm corn and herd cattle, mostly for their own survival.

Hospital officials in San Marcos said they had received 150 injured.

The president said more than 2,000 soldiers were deployed to help with the disaster. A plane had made at least two trips to carry relief teams to the area.