A strong, long 7.6-magnitude earthquake with an epicenter in Guerrero state on Tuesday, followed by an aftershock that shook central southern Mexico, swayed buildings in Mexico City and sent frightened workers and residents into the streets.
The U.S. Geological Survey set the intensity of the first quake at 7.6 and said the epicenter was 11 miles underground and was felt strongly in Oaxaca. Mexico's National Seismological Survey said the tremblor had an epicenter southwest of Ometepec in Guerrero state.
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 zones of the city.
But frightened workers and residents poured into the streets of the capital just minutes after noon local time (18:02 GMT).
President Felipe Calderon said there were no immediate reports of damage through his Twitter account. Telephone service was down in the city and throughout the area where the quake was felt.