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.