Updated at 10:40 a.m. ET
The most powerful earthquake to hit Mexico in decades struck late Thursday off the country's southern coast and could be felt hundreds of miles away in the capital. The 8.1-magnitude temblor is blamed for killing at least 15 people near the epicenter.
The quake triggered fears of a tsunami and was followed by at least 20 aftershocks.
The U.S. Geological Survey said the epicenter was located 102 miles west of Tapachula in Chiapas, not far from Guatemala, at a depth of about 43 miles.
USGS put the magnitude at 8.1, matching the strength of a powerful earthquake that struck Mexico City in 1985, killing thousands of people. However, Mexican President Enrique Peña Nieto said it measured 8.2, bigger than the 1985 quake. That would make it the strongest in well over a century.
"Unfortunately, there are reports of deaths," Peña Nieto tweeted. "My heartfelt condolences to the families."
The president said that 1.85 million users had lost electricity but that 1.38 million had their power restored after earthquake-related outages.
"We are assessing the damage, which will probably take hours, if not days," Peña Nieto told the nation hours after the quake struck, adding that the "population is safe" and there was no need for panic.
Reporter Emily Green in Mexico City, 650 miles from the epicenter, tells Morning Edition that she was on the street when she heard an earthquake warning klaxon and felt the ground shake. "It lasted a long time. It felt like more than a minute, but it was probably a minute."
Rodrigo Soberanes, who lives near the city of San Cristobal de las Casas in Chiapas state, was quoted by The Associated Press as saying his house "moved like chewing gum and the light and internet went out momentarily."
In Mexico City, power went out in several neighborhoods and windows were shattered at the main airport, according to Reuters.
The governor of Chiapas, Manuel Velasco Coello, said three people were killed in San Cristobal, including two women in a house collapse. "There is damage to hospitals that have lost energy," he said, according to the AP. "Homes, schools and hospitals have been damaged."
Two children were reportedly killed in neighboring Tabasco state, one when a wall collapsed. The other was a baby on a ventilator who died in a children's hospital when it lost power, the AP says.
Reuters reports that a number of buildings in parts of southern Mexico were severely damaged.
The U.S. Tsunami Warning System said waves of 3.3 feet above tide level were measured off Salina Cruz, Mexico, and smaller waves elsewhere. Hazardous tsunami waves were also possible on the Pacific coasts of several Central American countries, including Guatemala, El Salvador, Costa Rica, Nicaragua, Panama and Honduras, within three hours.
Authorities in the state of Chiapas are assessing the damage. Civil Defense in the state said on Twitter that it was sending teams out to help people and warned them of possible aftershocks.
In neighboring Guatemala, President Jimmy Morales said there were reports of damage and at least one death.