At least 60 people have died in the strongest earthquake to hit Mexico in 100 years.
The 8.1 magnitude quake off the southern coast late Thursday was stronger than a devastating 1985 temblor that flattened swathes of Mexico City and killed thousands.
President Nieto has declared a day of mourning, saying flags would fly at half mast out of respect for the dead and bereaved.
"The power of this earthquake was devastating, but we are certain that the power of unity, the power of solidarity and the power of shared responsibility will be greater," Pena Nieto said.
A huge rescue operation is under way in the worst-hit states of Tabasco, Oaxaca and Chiapas where people are feared trapped under rubble.
Prayers for Mexico!
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