The death toll from Mexico’s powerful earthquake has risen to 273, officials say, as rescuers race against the clock to reach trapped survivors.

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.

The news of the schoolgirl, dubbed Frida Sofia by local media, captivated the nation and the subject was trending worldwide on twitter with hundreds of heartfelt messages of support.

Mexican newspaper el universal later reported that, according to the Enrique RÉBSAMEN school, there was no child on their register called Frida SOFIA.

Mexico’s navy has since apologized for sharing incorrect information, adding that the search was for an adult.