Mexico's president says that the magnitude of the earthquake that hit the country overnight is 8.1, the biggest the country has seen in a century.
Enrique Pena Nieto confirmed at least five people have died. He also said that major damage has been caused and that 1 million initially had been without power following the quake, but that electricity had been restored to 800,000 of them.
He said that there have been 62 aftershocks and it's possible one as strong as 7.2 could hit.
The U.S. Geological Survey has reported that the quake had a magnitude of 8.1. It hit off the coast of southern Mexico, toppling houses in Chiapas state, causing buildings to sway violently as far away as the country's distant capital and setting off a tsunami warning.
Tsunami waves have also been measured off Mexico's Pacific coast after a major earthquake.
The Pacific Tsunami Warning Center says waves of 1 meter (3.3 feet) above the tide level were measured off Salina Cruz. Smaller tsunami waves were observed on the coast or measured by ocean gauges in several other places.
The center's forecast said Ecuador, El Salvador and Guatemala could see waves of a meter or less.
No threat was posed to Hawaii and the western and South Pacific.