Southern Mexico was rocked by a jarring, magnitude-6 earthquake, knocking out power in parts of Mexico City and Acapulco, swaying tall buildings and sending frightened people into the streets in their pajamas.
Civil defense officials in Mexico and the Pacific coast state of Guerrero, where the quake was centered, said there were no reports of any deaths or widespread damage. But dozens of buildings in Mexico City were evacuated amid reports that they suffered structural damage, and officials were inspecting them to determine if they were still safe.
Among them were a five-story apartment building that was leaning precariously and another graffiti-covered, art-deco apartment complex riddled with fissures. Some two dozen families, residents of both buildings, spent the night in the street or in their cars.
One person was injured falling down stairs trying to get out of a building.
The strong quake, which hit at 12:42 local time (0542 GMT) was felt strongly from the Pacific coast resort of Acapulco to the mountain capital of Mexico City because it was centered inland - 65 kilometers (40 miles) northwest of Acapulco - and just 29 kilometers (18 miles) below the earth's surface, the U.S. Geological Survey said.
Many of Mexico's earthquakes are centered out in the Pacific.
Gerard Fryer of the Pacific Tsunami Warning Center said the quake was too small and too far inland to produce a tsunami.
Several aftershocks followed, including one, pre-dawn magnitude-5.4 that was felt throughout much of southern Mexico.
Emergency officials reported a few small, isolated gas and water leaks, but they were quickly fixed. Mexico City Civil Defense Secretary Miguel Moreno Brizuela said the quake knocked out power to about 20 percent of the homes in the capital's downtown district, although it had been mostly restored by late morning. There were also reports of scattered outages in Acapulco.
About 100 people from one community near Acapulco were evacuated to a park after a nearby water treatment plant reported a chlorine leak, civil protection official Nadia Vela said.
At the high-rise, beachside Fairmont Acapulco Princess Hotel, hundreds of guests rushed outside, huddling on deck chairs as security officials used megaphones to urge them to remain calm.
"We flew out of bed. The building was shaking," said Marcy Olsen, 41, a manager of gas stations in Minnesota. "I said, 'I think this has to be an earthquake.' We looked out the door, and everyone was leaving."
She was on vacation with her husband, Brian, 46, and their 13-year-old twin daughters.
"Where we are from, there's no such thing," Brian Olsen said. "Blizzards and cold, yes, but no earthquakes."
Emergency medical teams attended to residents of Mexico City and tourists in Acapulco who suffered panic attacks.
The capital is built on a sandy lake bed that shifts and shimmies, magnifying earthquakes, and many still remember the magnitude-8.1 quake in 1985 that leveled parts of Mexico City, killing some 10,000 people.
Alfredo Sanchez, a 37-year-old construction worker renovating a century-old house in downtown Mexico City, was awoken by shouts from his co-workers to get up and take refuge under the concrete beams they had just installed in the old building.
"When I was lying down, I didn't feel it so much, but as soon as I got up, I felt it," said Sanchez, who stood outside on the sidewalk with his workmates after the temblor. "For our own safety, we got out."