A strong earthquake has shaken the southern Pacific coast of Mexico as well as the capital and several inland states, sending people into unseasonal torrential rains that were also bearing down on the coast.
The 6.4-magnitude quake in southern Guerrero state was centered about nine miles (15km) north of Tecpan de Galeana, according to the US Geological Survey (USGS), and was felt about 171 miles (277 km) miles away in Mexico City, where office workers streamed into the streets away from high-rise buildings.
There were no reports of injuries but varying reports of damage near the epicentre emerged throughout the day.
Among the damage was the collapse of a 30 yard section of highway bridge that was already under repair from last autumn's flooding and a magnitude-7.2 quake in the same area in April. Flooding of the detour route from heavy rain left the highway between the resort cities of Acapulco and Zihuatanejo closed.
Guerrero governor Angel Aguirre reported three homes collapsed in Zijuatanejo and 17 more unstable after the tremor. Local officials reported dozens of simple homes collapsed near the epicentre, though no one was injured. The governor also reported mudslides on other major highways, including the one connecting Acapulco with Mexico City.
Civil protection crews in Acapulco found no problems except scared citizens who were forced to take refuge in the heavy rain that was hitting the region.
In Mexico City, businesswoman Carmen Lopez was leaving a downtown office building when the ground began to shake. She dashed across the street to a leafy median as light poles swayed violently above her.
"That was just too scary," Ms Lopez said as she quickly started dialling her mobile phone to alert friends and family.
Behind her, thousands of people poured from neighbouring office buildings, following pre-planned evacuation routes to areas considered safe in case of falling glass.
The quake occurred at a depth of 15 miles (23km) and its epicenter was about 40 miles (66km) from that of the April 18 quake that shook central and southern Mexico.
The earlier quake occurred in a section of the Pacific Coast known as the Guerrero Seismic Gap, which is a 125-mile (200km) section where tectonic plates meet and have been locked, causing huge amounts of energy to be stored up with potentially devastating effects, the USGS said. It said a magnitude-7.6 tremor struck in the section in 1911.
The US agency said the most recent quake was an aftershock of the April 18 tremor.