MEXICO CITY - Desperate rescue workers scrabbled through rubble on Wednesday in a floodlit search for dozens of children feared buried under the rubble of a Mexico City school, one of hundreds of buildings wrecked by the country's most lethal earthquake in a generation.

The magnitude-7.1 quake killed at least 225 people, nearly half of them in the capital, 32 years to the day after a devastating 1985 earthquake and less than two weeks after a powerful tremor killed nearly 100 people in Mexico's south.

China has extended deep condolences to the victims and expressed heartfelt sympathy to their bereaved families, the Mexican government and people in affected areas, Foreign Ministry spokesman Lu Kang said on Wednesday. "China has paid attention to the earthquake and the heavy casualties it has caused," Lu said, adding that "China believes that the Mexican people can overcome the disaster and rebuild their lives".