A magnitude 7.2 earthquake struck southeastern Mexico on Friday night, with the epicenter in the state of Oaxaca, the US Geological Survey reported.
The USGS initially reported a magnitude of 7.5 but revised it downward.
An earthquake alert was issued in Mexico City and buildings were evacuated there, CNN's Leyla Santiago said. Video showed people streaming out of buildings and into the streets.
No reports on injuries or damage were immediately available. The center of the earthquake was about 348 kilometers (216 miles) southeast of Mexico City.
Mexican President Enrique Peña Nieto tweeted that the earthquake was northeast of Pinotepa Nacional, in Oaxaca, and that "protocols have been activated."
Two deadly earthquakes struck Mexico in September.
A magnitude-8.1 earthquake struck off the southern coast on September 8, killing at least 90. On September 19, a magnitude 7.1 earthquake hit Mexico City, killing at least 216 people.