Strong shaking was felt in the Mexican capital and office workers streamed into the streets when a magnitude 6.4 earthquake struck the country's southern coast Thursday morning, the Associated Press reported.
There were no immediate reports of injuries or damage and only mild shaking was felt near the resort city of Acapulco, the wire service reported.
The U.S. Geological Survey reported the epicenter was located near Tecpan de Galeana, less than 190 miles southwest of Mexico City.
The agency downgraded the quake from magnitude 6.8.
According to the AP:
Mexico City is vulnerable to distant earthquakes because much of it sits atop the muddy sediments of drained lake beds. They jiggle like jelly when the quake waves hit.
A 7.2-magnitude quake hit the same region last month.
Wednesday night, a 3.3-magnitude quake gave the Los Angeles area a jolt.