MEXICO -- A strong earthquake has shaken central southern Mexico, causing buildings to sway in Mexico City and sending frightened workers and residents into the street.
There are no reports yet of major damage or injuries.
The U.S. Geological Survey puts the intensity of the quake at 7.6. It was centered in the Mexican state of Guerrero, 15 miles east of Ometepec.
Mexico's National Seismological Survey said the temblor had an epicenter southwest of Ometepec.
It was six miles underground.
Residents rushed into the streets after feeling the temblor in Mexico City.
Tourists and residents also felt the earthquake in the resort city of Acapulco.
Mexican President Felipe Calderon said in a Twitter post that there were no immediate reports of serious damage.
"There are some broken windows, much fear, much panic," he said.
Residents in the southwestern states of Oaxaca and Guerrero and the eastern state of Veracruz reported that phone service had been knocked out in their areas.
Authorities were investigating reports of damaged or destroyed homes in Ometepec, said Alejandra Garcia of the Guerrero state police.
Authorities in Mexico City were surveying buildings, schools and hospitals to evaluate damage, Mayor Marcelo Ebrard said.
A pedestrian bridge fell on a bus during the quake, he said, but there were no injuries.
Some buildings had cracks and broken windows, he said in a Twitter post.
Earthquakes are a frightening experience for the more than 20 million residents of Mexico City, where about 10,000 people perished in a massive quake in 1985.
The city, built on volcanic ash and clay, is particularly vulnerable to temblors.