A 6.7-magnitude earthquake struck Mexico's western Guerrero state today, shaking buildings and causing panic just over 100 miles away in the nation's capital.
There were no immediate reports of damage or injuries.
The US Geological Service estimated the quake's magnitude at 6.7, after an initial reading of 6.8. It said the quake was centred about 26 miles south west of Iguala in Guerrero - 103 miles south-south west of Mexico City.
High-rises swayed in the centre of Mexico City and people were temporarily herded out of some shopping centres.
People in one part of the capital's wealthy Condesa neighbourhood ran out of their houses and gathered in the streets, hugging each other while some shook and began to cry.
On one street, a group of women joined hands in a circle, closed their eyes and began to pray.
Mexico City's mayor Marcelo Ebrard said on Twitter that no major damage had been reported, although there were some power failures in parts of the city.