Residents felt intense tremors in the Mexican states of Chiapas and Oaxaca as well as in Guatemala and El Salvador, AFP journalists confirmed. Authorities have not yet reported any victims.
The US Geological Survey (USGS) said the quake's epicenter was located offshore some 48 kilometers (30 miles) from the town of Aquiles Serdan, at a depth of 18 kilometers.
The Mexican seismological service recorded more than 30 aftershocks of various magnitudes, measuring as high as 6.8.
The US government issued a tsunami warning for Pacific coastal areas of Mexico and Guatemala, but later said the threat had passed.
In Tuxtla Gutierrez, the state capital of Chiapas, there were scenes of panic in the few tall buildings of the city, according to an AFP journalist in the area.
"It feels horrible up there," Araceli Sanchez, a government employee who was in a 15-story building, told AFP.
"There were people who cried," she added after fleeing down the emergency stairs.
Mexican President Claudia Sheinbaum said she had spoken to the governors of the affected states, while Navy Secretary Raymundo Morales told reporters: "There are no serious effects."
In Guatemala City, multiple buildings were evacuated and classes were canceled in some areas closest to the Mexican border.
Mexico City, hard-hit by two powerful earthquakes in 1985 and 2017, is more than 800 kilometers from the epicenter, though some reported on social media that they had felt it.
Some tall buildings were evacuated as a precaution.
Mexico and Central America are located on different tectonic plates whose movements have turned the region into one of the most earthquake-prone in the world.
AFP
Comment: The USGS reported a shallow aftershock of mag. 6 about half an hour later.