Updated at 1 a.m. ET: The Associated Press reports that Humberto Calvo, undersecretary of Guerrero's Civil Protection agency, said a third person died in the small town of Ixcateopan.

Updated at 11:20 p.m. ET: Telemundo reports that at least two people were killed: an 11-year-old child died when the roof of a taqueria collapsed in Iguala, near the epicenter, and a driver was killed and two women injured when a boulder was dislodged by the quake and hit their Ford truck on the Sol highway between Acapulco and Mexico City.

Earlier story:

ACAPULCO, Mexico -- A 6.5-magnitude earthquake struck the region north of Acapulco on Saturday night, and people in Mexico City fled into the streets. 

The epicenter was about 82 miles north of Acapulco in the southwestern state of Guerrero and about 40 miles deep, the U.S. Geological Survey reported. The quake was intially reported as a 6.8 but downgraded to 6.5. 

Telemundo reported that at least two people were killed..

In Acapulco, hundreds of anxious tourists congregated in the streets after fleeing rocking buildings. Authorities said they had found no structural damage and had no reports of injuries in the Pacific resort.

Buildings in Mexico City, about 100 miles northeast of the epicenter, swayed during the quake, but there were no immediate reports of major damage there.

People in one part of the capital's upscale Condesa neighborhood ran out of their houses and gathered in the streets, hugging each other while some shook and began to cry. On one street, a group of women joined hands in a circle, closed their eyes and began to pray.

"Please God, help us and let everything be OK," said one. "It's OK. It's OK. Everything is OK."

Reuters reporters in Mexico City said the earthquake seemed to go on for an unusually long period.

"I was dreadfully afraid, I thought it was never going to end," said Laura Gonzalez, who was drinking in a bar in the capital when the quake struck.

Power was knocked out in parts of the capital, but Mexico City Mayor Marcelo Ebrard said water services, the subway and the airport were working normally.

Parts of Mexico City rest on the shaky soil of a former lake bed, which tends to magnify the effect of earthquakes. An 8.1-magnitude quake in 1985 killed as many as 10,000 people in the city.

This article includes reporting from msnbc.com staff, The Associated Press and Reuters.

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