The 7.6 magnitude earthquake struck 25km east of Ometepec, in Guerrero state.
A strong earthquake has struck Mexico, damaging buildings, scaring residents and prompting evacuations across the capital city, but there were no reports of serious damage..
The United States Geological Survey (USGS) said the earthquake had a magnitude of 7.6 and put the epicentre at 25km east of Ometepec, in Guerrero state.
There were no immediate reports of damage, the Mexican President Felipe Calderon said on his Twitter account.
The quake was felt in Oaxaca state, next to Guerrero state, but no damage was reported there, according to local TV.
The earthquake was followed by a strong aftershock.
Witnesses said that office workers and residents were sent running into the streets in wealthy districts and poor neighbourhoods.
Sirens could be heard across the city, and police helicopters are crisscrossing the skies.
Mexico City Mayor Marcelo Ebrard's Twitter account said the water system and other "strategic services" were not experiencing problems and no damage was reported in the central or northern areas of the city.