President Enrique Peña Nieto said that rescuing and attending to those injured by Tuesday’s 7.1 magnitude quake would remain “the highest priority”.
The quake toppled dozens of buildings and left millions without electricity.
Rescuers believe that people may still be trapped alive in as many as 10 buildings in Mexico City alone.
The new death toll was announced by Mexico’s emergency services chief and the president’s office.
As rescue operations continued for a third day, much attention was focused on Enrique Rébsamen school in the capital, where the body of a female teacher was found overnight.
More than 500 members of the army and navy together with 200 police officers and volunteers have been working at the site.
Officials say 11 children were rescued there, while 19 children and six adults died.
Assistant Navy Secretary Angel Enrique Sarmiento said that rescue teams now believed an adult person – probably a school employee – may be still alive under the rubble.
He added that all pupils had now been accounted for – either alive or dead.
Several officials had earlier reported that a girl was trapped alive under the rubble.
Rescuers at times were demanding silence from bystanders around them in order to hear any calls from survivors.
The BBC’s Rajini Vaidyanathan, in Mexico City, has been told there might be as many as 30 people trapped inside a collapsed six-storey apartment and office block.
The country’s elite team of rescuers, known as “the moles”, are leading the volunteer rescue efforts. The group was formed in the wake of the devastating 1985 earthquake that killed up to 10,000 people.
Police have stepped up patrols in areas hit by the quake to prevent vandalism and looting.
20 September 2017
Mexico is no stranger to earthquakes and earlier this month an 8.1 magnitude tremor in the south left at least 90 people dead.
Tuesday’s tremor struck shortly after many people had taken part in an earthquake drill on the 32nd anniversary of the deadly 1985 quake.