(CBS/AP) MEXICO CITY - A strong, long 7.6 earthquake with an epicenter in Guerrero state shook central southern Mexico 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 at 7.6 on the Richter scale and said the epicenter was 11 miles underground. Mexico's National Seismological Survey said the temblor had an epicenter southwest of Ometepec.
Mexico City Mayor Marcelo Ebrard's Twitter account said the water system and other "strategic services" were not experiencing problems.
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.
"I have problems with pressure, I felt I was going to faint," said Rosa Maria Lopez Velazquez, 62, outside a mall in Mexico City.
There were no immediate reports of major damage or injuries.
Reuters reported of problems with traffic and cell phone lines in the capital after the quake hit.
The quake was felt in southern Oaxaca state next to the epicenter in Guerrero.
"It was very strong, but we didn't see anything fall," said Irma Ortiz, who runs a guesthouse in Oaxaca. She said their telephones are down, and that the quake shook them side-to-side.
© 2012 CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.
To comment, the following rules must be followed:
Comments may be monitored for inappropriate content, but the station is under no legal obligation to do so.
If you believe a comment violates the above rules, please use the Flagging Tool to alert a Moderator.
Flagging does not guarantee removal.
Multiple violations may result in account suspension.
Decisions to suspend or unsuspend accounts are made by Station Moderators.
Questions may be sent to firstname.lastname@example.org. Please provide detailed information.