Authorities have said at least 100 people have been killed after a powerful 7.1 magnitude earthquake struck central Mexico.
At least 54 people have died in the central Mexican state of Morelos following the quake, according to state officials.
Twenty-six people died in the state of Puebla, where a school also collapsed. The state is also where the epicentre of the quake struck.
It hit 8km southeast of Atencingo in Puebla at a depth of 51km, the US Geological Survey said.
Sirens blared as first responders rushed through the streets of Mexico City, where Mayor Miguel Ángel Mancera said at least four people were killed.
Mexican President Enrique Peña Nieto said that 27 buildings have collapsed in Mexico City.
The quake shook buildings in the capital, sending people fleeing into the street.
Power was cut to 3.8 million customers, the national electricity company CFE said
The earthquake hit only hours after many people participated in earthquake drills around the nation on the anniversary of the devastating quake that killed thousands in Mexico City in 1985.
Dozens of police, rescue workers and neighbours dug through the wreckage of collapsed buildings in Mexico City.
At least one survivor was pulled from a collapsed building in the city's busy Condesa neighborhood, and another person was rescued from a six-story apartment building nearby.
In Cuernavaca, a city in Morelos that is a popular destination for weekend visitors from Mexico City, there were reports on local radio of people trapped beneath collapsed buildings.
Mexican TV and social media showed cars crushed by debris.
Mexican stocks and the peso currency dropped on news of the earthquake, and Mexico's stock exchange suspended trading.
Mr Peña Nieto has called the county's National Emergency Committee to "assess the situation and to coordinate actions".
Mexico airport has halted all operations following the quake.
God bless the people of Mexico City. We are with you and will be there for you.
— Donald J. Trump (@realDonaldTrump) September 19, 2017
US President Donald Trump vowed the US would "be there" for the US's southern neighbour.
He said on twitter, "God bless the people of Mexico City. We are with you and will be there for you."
Earthquakes of magnitude 7 or above are regarded as major and are capable of causing widespread heavy damage
A powerful 8.1 quake hit Mexico earlier this month, killing at least 98 people.
