At least 21 children and five adults died at a primary school which collapsed in Mexico City during Tuesday's quake, the government says.
The shallow, 7.1 magnitude quake killed at least 225 people in total and caused major damage across states in the centre of the country.
Desperate searches for survivors under the rubble are continuing.
Dozens of buildings collapsed, including several churches where worshippers were killed.
Families with young children could be seen sleeping outside their homes in the street in the capital overnight.
The tremor struck shortly after many people had taken part in an earthquake drill, exactly 32 years after another quake killed thousands in the capital.
Mexico is prone to earthquakes and earlier this month an 8.1 magnitude tremor in the south left at least 90 people dead.
Enrique Rébsamen primary school collapsed in Mexico City's southern Coapa district.
Confirming the death toll, Education Minister Aurelio Nuño†said 11 people had been rescued while two children and an adult were missing.
Credit: BBC News