At least five people were killed as a magnitude-8.2 earthquake rocked southern Mexico late Thursday night, causing people to flee into the street, buildings to sway, and lights to go out in Mexico City.

Mexican President Enrique Pena Nieto called the quake the strongest the country has seen in a century.

The powerful quake occurred 59.7 miles southwest of Pijijiapan, Mexico, off the coast of Chiapas at 11:49 p.m. local time (12:49 a.m. ET), according to the U.S. Geological Survey. The depth of the earthquake was 22 miles, the USGS said.

The governor of Chiapas, Manuel Velasco, told local media at least three people had been killed in San Cristobal de las Casas, a city in the region.

Two children were reported dead by The Associated Press in Tabasco, the state just north of Chiapas. Tabasco Gov. Arturo Nunez told The Associated Press one child died when a wall collapsed on them, while a baby died when electricity went out at a hospital where the infant was on a ventilator.

Nieto said 1 million customers were without power in the immediate aftermath of the quake, but that 200,000 remained without power as of 4 a.m. ET on Friday.

Authorities in Oaxaca, west of the state of Chiapas, were seen assessing damage to the area early Friday, including to a hotel. 

The Mexico City fire department told ABC News that there were no casualties. 

 Mexico's Pacific coastal areas -- as well as the coastlines of Guatemala, Honduras, El Salvador and Costa Rica -- experienced some tsunami waves, with waves over 3 feet off Salina Cruz.

"Based on all available data Hazardous tsunami waves are forecast for some coasts," the National Weather Service Tsunami Warning Center said in an alert. "Tsunami waves reaching more than 3 meters above the tide level are possible along some coasts of Mexico."

Mexican President Enrique Pena Nieto tweeted that the country's National Security Committee had been activated. 

 A number of aftershocks were also being reported in the original area off the southern coast. They ranged in magnitude from 3.7 to 5.7, and Nieto said the country had experienced 62 total in the four hours following the initial earthquake.

source: AFP