A magnitude 7.1 earthquake jolted central Mexico on Tuesday, collapsing some buildings, cracking the facades of others and scattering rubble on streets on the anniversary of a devastating 1985 quake.

People were trapped inside various buildings that caught fire in Mexico City, a civil protection official told local TV.

The quake caused buildings to sway sickeningly in Mexico City and sent panicked office workers streaming into the streets, but the full extent of the damage is not yet clear. Mexican media broadcast images of several collapsed buildings in heavily populated parts of the city.

The U.S. Geological Survey said the quake was centred near the Puebla state town of Raboso, about 123 kilometres southeast of Mexico City.

Puebla Gov. Tony Galil tweeted that buildings had been damaged in the city of Cholula, including collapsed church steeples.

In Mexico City, thousands of people fled office buildings and hugged to calm each other along the central Reforma Avenue as alarms blared, and traffic stopped around the Angel of Independence monument.

In the Roma neighbourhood, which was struck hard by the 1985 quake, piles of stucco and brick fallen from building facades littered the streets. At least one large parking structure collapsed. Two men calmed a woman seated on a stool in the street, blood trickling from a small wound on her knee.

People react as a real quake rattles Mexico City on Sept. 19 as an earthquake drill was being held in the capital. (Yuri Cortez/AFP/Getty Images)

At a nearby market, a worker in a hard hat walked around the outside warning people not to smoke as the smell of gas filled the air.

Market stall vendor Edith Lopez, 25, said she was in a taxi a few blocks away when the quake struck. She said she saw glass bursting out of the windows of some buildings. She was anxiously trying to locate her children, whom she had left in the care of her disabled mother.

Pictures fell from office building walls, objects were shaken off of flat surfaces and computer monitors toppled over. Some people dove for cover under desks. Local media broadcast video of whitecap waves churning the city’s normally placid canals of Xochimilco as boats bobbed up and down.

Reuters reports that the Mexico City airport and the stock exchange suspended operations after the quake.

People react as a real quake rattles Mexico City Tuesday while an earthquake drill was being held in the capital. ( Yuri Cortez/AFP/Getty Images)

Earlier in the day, workplaces across the city held preparation drills on the anniversary of the 1985 quake, a magnitude 8.1 temblor, which killed at least 5,000 people and devastated large parts of Mexico City.

Twelve days ago, shortly before midnight on Sept. 7, an 8.1 magnitude earthquake hit Mexico, killing almost 100 people.

Much of Mexico City is built on a former lake bed, and the soil is known to amplify the effects of earthquakes even hundreds of kilometres away.

Gustavo Serrano, BuzzFeed Mexico’s social media editor, posted this video on Twitter: