MEXICO CITY • Rescuers laboured against long odds into the dawn yesterday to save a 12-year-old schoolgirl and other survivors who may be trapped beneath crumpled buildings in central Mexico following the country's deadliest earthquake in 32 years.

More than 50 survivors have been plucked from several disaster sites since Tuesday afternoon's 7.1-magnitude quake, leading to impassioned choruses of "Yes we can!" from the first responders, volunteers and spectators gathered around the ruins.

At least 237 others have died and 1,900 were injured.

As the odds of survival lengthened with each passing hour, officials vowed to continue with search-and-rescue efforts, such as the one at a collapsed school in southern Mexico City where navy-led rescuers could communicate with the 12-year-old girl but were unable to dig her free.

Eleven other children were rescued from the Enrique Rebsamen School, but 21 students and four adults there were killed.

Rescuers previously had seen a hand protruding from the debris and the girl wiggled her fingers when asked if she was still alive, according to broadcaster Televisa.

But some 15 hours into the effort, Admiral Jose Luis Vergara said rescuers still could not pinpoint her location. "There's a girl alive in there, we're pretty sure of that, but we still don't know how to get to her," Adm Vergara told Televisa.

Throughout the capital, rescue crews, who were joined by volunteers, used dogs, cameras, motion detectors and heat-seeking equipment to detect survivors.

Businessmen in ties, students in jeans, doctors in scrubs and other ordinary folk joined in, rushing onto and into the mangled remains of homes, schools and offices.

The overwhelming outpouring of sympathy resulted in volunteer rescuers being turned away at many sites if they did not bring their own helmets.

Some 52 buildings collapsed in Mexico City alone, and more in the surrounding states.

Officials said the quake killed 102 people in Mexico City and the remaining 135 victims were from five surrounding states.

At least nine Latin American countries pledged to rush in search-and-rescue teams or technical assistance - with crews from Panama and El Salvador already on the job - as did the United States, Spain, Japan and Israel.

The earthquake struck about 150km south-east of Mexico City on Tuesday afternoon, shattering glass, shearing off sides of buildings and leaving others in dusty piles of destruction.

Mexico was still recovering from another powerful quake less than two weeks ago that killed nearly 100 people in the south of the country.

REUTERS, AGENCE FRANCE-PRESSE