The 8.1 magnitude quake off the coast of Chiapas state was stronger than a 1985 temblor that flattened swaths of Mexico City and killed thousands. However, its greater depth and distance helped save the capital from more serious damage.
On Saturday, authorities in the southern state of Oaxaca said there were 71 confirmed fatalities there, many of them in the town of Juchitan, where the rush to bury victims crowded a local cemetery at the weekend.
Another death was confirmed in neighboring Chiapas late on Sunday, bringing the total there to 16, a spokesman for local emergency services said. A further four deaths have also been registered in Tabasco state to the north.
Television footage from parts of Oaxaca showed small homes and buildings completely leveled by the quake, which struck the narrowest portion of Mexico on the isthmus of Tehuantepec.
Aftershocks continued into Sunday, and scores of people were wary about returning to fragile buildings hammered by the initial tremor, sleeping in gardens, patios and in the open air.
Piles of rubble lay strewn around damaged streets, where the shock was still visible on the faces of residents.
Oaxaca Governor Alejandro Murat told Mexican television the quake hit 41 municipalities and had likely affected around one in five of the state's 4 million-strong population.
"We're talking about more than 800,000 people who potentially lost everything, and some their loved ones," he said on Sunday.
In Juchitan alone, more than 5,000 homes were destroyed. Hundreds of thousands of Mexicans were temporarily left without electricity or water, and many in the south were evacuated from coastal dwellings when the quake sparked tsunami warnings.
In Chiapas, some 41,000 houses were damaged, governor Manuel Velasco said, estimating nearly 1.5 million people were affected.
President Enrique Pena Nieto declared three days of national mourning and pledged to rebuild shattered towns and villages.
However, some residents interviewed expressed frustration that the poor southern regions were still not getting the help they needed from the richer north and center of Mexico.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)