At least 138 people have been reported dead after a devastating earthquake shook Mexico City and the surrounding areas, destroying buildings and sending residents scrambling to help anybody caught under rubble.
The steadily rising death toll made it the second deadliest earthquake to hit Mexico since a 1985 catastrophe that killed thousands.
Videos and images showed rubble covering streets, cars smashed by fallen debris, and groups of people working together to lift large metal beams that appeared to have fallen during the trembling.
The powerful earthquake registered with as 7.1 magnitude tremor, according to the US Geological Survey (USGS), and occurred on the anniversary of the cataclysmic 1985 quake that ravaged Mexico City and left thousands dead.
Earthquake drills were reportedly planned for the day. Mexico's seismological survey pegged the preliminary magnitude just a bit smaller, at 6.8, and indicated that the epicentre was located in the nearby municipality of Puebla. That community is about 40 miles southeast of the capital.
One visitor to the city, who asked to be identified simply as Juan, was in a penthouse building in the city when the quake struck.
He sent The Independent a text which said: "One word: apocalyptic. We heard the earth roar and the buildings creak. My heart was still pounding fast, minutes afterwards."
Fatalities were climbing in the country's capital of Mexico City, where Mayor Miguel Angel Mancera said at least 30 people had died and structural damage was widespread.
The streets were strewn with dust and rubble from at least 44 collapsed buildings. Mr Mancera offered a glimmer of hopefulness, saying 50 to 60 people had been pulled alive from the detritus.
Officials in the central Mexican state of Morelos said that there were at least 54 people killed as a result of the earthquake in his state, with 12 of those deaths occurring in the city Jojutla and four more in the state capital of Cuernavaca.
Nine deaths were reported by Governor Del Mazo of the State of Mexico, a revision from the initial two deaths that were reported in that state. At least another 26 deaths were reported in Puebla.
Just hours after the initial reports of the earthquake, the disaster was trending on Twitter, and Facebook's check-in system for survivors during high concern situations had been activated.
President Donald Trump, who had taken nearly a week to respond to a devastating earthquake in Mexico earlier this month, tweeted that the United States stood by the people of Mexico City.
"God bless the people of Mexico City," Mr Trump wrote in a tweet. "We are with you, and will be there for you."
At least one video, posted live on Twitter's Periscope, showed a group of men working together to try and move large metal beams. Nearby, cars were smashed by debris that had been shaken loose by the earthquake.
In another video, a building swayed sickeningly during the rumbling.
Another showed people packing into a hallway with lights swaying above them, before the building appeared to lose power and the lights went out.
In yet another video, the whole facade of a building that appears to be about 10 stories falls to the ground.
In a school in Mexico City's Roma district, Gala Dluzhynska described running alongside at least 11 other women from the second floor of the building.
She described a terrifying scene to the Associated Press outside of her former school, saying that she and others had scrambled down stairs to get out of the building amid choking dust.
At one point she fell down, and was trampled by others before someone going by grabbed her and helped her up.
"There weren't any stairs anymore, only rocks," she said.
Once she and the others got outside of the building, they attempted to push against the fencing until a security guard finally came and let them out. Outside was all rubble, she said. They were also still looking for one friend.
The earthquake comes just weeks after another massive earthquake hit near the souther states of Oaxaca and Chiapas, sending trembles through the area into Guatamala, and leaving at least 98 people dead.
That quake was an 8.1 magnitude quake, and resulted in several aftershocks registering at about 5.0 magnitude.
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