A powerful 7.1 earthquake rocked central Mexico on Tuesday, collapsing homes and bridges across hundreds of miles, killing at least 217 people and sending thousands more fleeing into the streets screaming in a country still reeling from a deadly temblor that struck less than two weeks ago.
Entire apartment blocks swayed violently in the center of Mexico City, including in the historic districts of El Centro and Roma, crumbling balconies and causing huge cracks to appear on building facades.
Panic spread through the city's core; rescue vehicles raced toward damaged buildings, and neighbors took on heroic roles as rescuers.
Firefighters and police officers scrambled to pull survivors from a collapsed elementary and secondary school where children died.
"There are 22 bodies here — two are adults — 30 children are missing and eight other adults missing. And workers are continuing rescue efforts," President Enrique Peña Nieto announced Tuesday night.
At least 86 people were reported killed and 44 buildings severely damaged in the capital alone. Twelve other people died in the surrounding state of Mexico, 71 across the state of Morelos, 43 in Puebla state, four in Guerrero state and one in Oaxaca, according to Mexican officials.
The temblor struck 32 years to the day after another powerful earthquake that killed thousands and devastated large parts of Mexico City — a tragedy that Peña Nieto had commemorated earlier Tuesday.
Around 11 a.m., Julian Dominguez heard alarms sounding in the neighborhood of Iztapalapa, part of a citywide drill to mark the anniversary of the magnitude 8.0 quake. Schools and other buildings evacuated, but he kept working at his computer.
About two hours later, Dominguez, 27, started to feel the building move, and alarms sounded again.
"It started really slowly," he said, but within seconds it was clear that this was no drill.
Dominguez raced down a flight of stairs. Crowds of people already had gathered outside. Parents were crying, worried for their children still in school.
"It was strange that it fell on the same day … as another earthquake that caused so much damage," Dominguez said.
The federal government declared a state of disaster in Mexico City and dispatched 3,428 troops to affected areas there and in nearby states.
"We are facing a new emergency in Mexico City, in the state of Puebla and Morelos, following the 7.1 magnitude earthquake," Peña Nieto said, adding that he had asked all hospitals to help care for the injured.
On Amsterdam Street, a normally tranquil road that rings a major park in the upscale Mexico City neighborhood of Condesa, a large apartment building disintegrated into a pile of concrete and dust.
Hundreds of residents helped a team of soldiers, police officers and firefighters search the rubble for survivors. Many of the men were shirtless in the late summer heat, and everyone was covered with dust.
Juan Jose Martinez, 52, felt the earthquake at his home several miles away. There was no damage to his neighborhood, so he and three relatives grabbed shovels and construction helmets and set out on foot to Condesa.
"What else would we do?" he said. "This is our Mexico. Everybody needs help sometimes."
Some rescuers commandeered shopping carts from a nearby supermarket and formed a human chain to haul away rubble. Several times, a warning went up about a possible aftershock or gas leak, sending hordes of panicked people running.
But there were few places that would be safe. Amsterdam, like many streets in Condesa, is narrow and lined with trees and power lines, all of which could turn deadly in an aftershock.
The neighborhood was filled with thousands of dazed survivors too afraid to return to their homes. They stood around holding their heads and checking social media feeds on their phones. Many ducked into their apartments to bring food and water for rescuers.
At Xochimilco, the famed series of canals plied by gaily decorated boats, the quake set off large waves that rocked the boats filled with tourists.
In Roma, an upscale neighborhood that experienced some of the worst destruction in the 1985 earthquake, several low-rise buildings collapsed Tuesday. Among them was a commercial structure that housed a furniture store on the first floor.
Itzel Hernandez Galvan, 21, was in her car, about to head home from her job at a marketing firm, when she heard people screaming and realized that part of the building was about to collapse onto her car. She opened the door and ran as half of the building broke off, crushing her car and taking out trees and power lines.
"I ran, and I survived," she said, still covered in dust. Others weren't so lucky. Several people were buried alive, she said.
Rescue workers managed to pull at least eight survivors from the rubble, but Galvan said she saw a child who had been killed.
As a large crowd gathered, Mexican soldiers labored to clear away slabs of concrete. At one point, the soldiers thought they heard someone calling out for help from beneath the rubble and appealed for silence. But after some time, they determined that it was nothing.
Most people were at work or at school when the earthquake hit. Across the capital, the survivors poured into the streets to walk home, searching for information about loved ones and posting the names of the missing on trees and lampposts. Public transportation had ceased to function in a sprawling city so large it can take three hours to get home.
"It's very horrendous," said Guillermo Lozano, the humanitarian and emergency affairs director for World Vision Mexico, a Christian humanitarian organization. "Everything was moving — the stairs were moving, things were falling down."
Among the destroyed buildings was a supermarket where survivors could be heard crying out for help, he said. Staff members at a children's hospital were tending to patients in the streets.
Building standards have improved since the 1985 quake, Lozano said, but there are many old buildings in the city, which were among the worst-hit.
When the quake struck, he was in a meeting coordinating relief efforts for southern Mexico, where at least 90 people died in another powerful temblor on Sept. 7.
"We will need a lot of help," Lozano said.
Authorities in Morelos reported major damage to the cities of Jojutla, Cuernavaca and Axochiapan.
"This is the first time in the history of Morelos that we have experienced something like this — a 7.1 magnitude earthquake," the state governor, Graco Ramirez, told reporters. "We're going to work hard overnight to try and rescue as many victims as we can find."
He said Morelos was receiving assistance from other nearby states. "We're all united and working together," Ramirez said. "There is no doubt that we will recover from this."
Mexico sits in one of the world's most seismically active areas, as the floor of the Pacific Ocean south of the country is sliding underneath the North American plate. Mexico City is prone to major damage in earthquakes because it was built on an old lake bed, which amplifies the shaking.
The U.S. Geological Survey calculated the magnitude of Tuesday's temblor at 7.1 and said the epicenter was about 80 miles southeast of Mexico City in the state of Puebla.
The city Puebla, about 60 miles southeast of Mexico City, also appeared to have suffered significant damage. Social media were filled with photographs of buildings that had collapsed into the streets, and there were reports that some of the city's famed ornate churches, erected in the colonial era, had been damaged.
Susan Hough, a USGS seismologist, said the quake may have been related to the one that struck off the coast of Mexico's Oaxaca state on Sept. 7, which the government calculated as a magnitude 8.2 and her agency as an 8.1.
"An 8.1 is big enough that having an aftershock this big and this distant — it isn't too surprising," Hough said. "It's unusual, but it fits in with the picture that we've grown to understand."
News of the latest disaster spread fear across the republic.
Mariela Alvarez, 30, was getting her nails done in San Vicente in the coastal state of Nayarit when she heard about the earthquake. She immediately thought of her 25-year-old sister, Gabriela Alvarez, who has lived in Mexico City for about five years.
She called her sister five times, growing more and more nervous every time she got her voicemail. "I imagined terrible things," Mariela said. "I was really scared."
She reached out to her father, who was at work. He told her that he had heard from Gabriela. She was fine.
"We could talk to her and so we feel calm, but there are people who still don't know," Mariela said.
As night fell, volunteers carried food, water, flashlights and other basics to people camping out in streets still littered with glass and debris.
As night fell on Mexico City, entire neighborhoods were plunged into darkness. Authorities begged residents in less affected areas to donate flashlights and lanterns so rescuers could keep working though the night.
Many were too frightened to return home and wandered the streets toting luggage and pets, looking for safer ground. Strangers offered strangers places to stay. They looked after one another.
In Condesa, an eight-story building threatened to collapse near an area where volunteers were collecting donations of food, water, batteries and flashlights. Despite fears of aftershocks — every few moments a panicked shout went up — the volunteers stayed on to help, working into the night.
Times staff writers Linthicum reported from Mexico City, Lin from San Francisco and Zavis and Vives from Los Angeles. Special correspondent Cecilia Sanchez and staff writer Brittny Mejia contributed to this report from Mexico City and Nayarit, Mexico, respectively.
4:25 a.m. Sept. 20: This article was updated with a revised death toll.
11:20 p.m.: This article was updated with a revised death toll.
9:25 p.m.: This article was updated with a new death toll and accounts from eyewitnesses.
7:45 p.m: This article was updated with the death toll rising to at least 139, a state of disaster declared in Mexico City and other details.
5:50 p.m.: This article was updated with the latest breakdown of casualties according to Mexico's National Center for the Prevention of Disasters, details of the devastation and quotes from survivors.
4:05 p.m.: This article was updated with the death toll rising to at least 105.
3 p.m.: This article was updated with four deaths reported in Mexico City, description of the rescue efforts and other details.
1:50 p.m.: This article was updated with 42 deaths reported in Morelos.
1:30 p.m.: This article was updated with two deaths reported and to include comments from Angel Mancera and Alfredo del Mazo.
12:50 p.m.: This article was updated throughout with staff reporting.
12:35 p.m.: This article was updated throughout with additional details and background.
12:05 p.m.: This article was updated with a revised magnitude estimate and additional details.