At least twelve people were killed in Mexico's Chiapas state, Governor Manuel Velasco Coello reported.
On Friday, Mexico suffered an earthquake measuring 8.2 on the Richter scale. In 1985, an earthquake measuring 8.0 on the Richter scale caused the deaths of 5,000 people.
Coello called on residents living near the coast to leave their homes after the Pacific Tsunami Warning Center (PTWC) warned of a tsunami measuring up to three meters high, which would harm coastal cities.
"Hospitals lost electricity, causing heavy damage," Coello said. "Homes, schools, and hospitals have suffered severe damage."
Eduardo Mendoza, who runs Mexico's emergency services, said Hurricane Katia's passage over Mexico made rescue efforts more difficult.
"The heavy rains which came as a result of the storm can transfer disease," he said. "Large trucks are having difficulty reaching the affected areas, so residents are attempting to bring aid via private cars.
Residents in affected areas need basic medical supplies, which can help injuries and trauma. Mexican President Enrique Peña Nieto said Friday's earthquake was the strongest "in a century."
"At least a million people were left without electricity immediately after the quake, but we have succeeded in restoring electricity to most of the affected cities," he said.
In a series of tweets, Nieto announced school closings in Mexico City and the states of Chiapas, Guerrero, Hidalgo, Mexico, Oaxaca, Puebla, Tabasco, Tlaxcala, and Veracruz.
Suspension of classes would allow experts to determine the damage to schools, he explained.
Nieto urged residents to check their homes and ensure they are not on the verge of collapse.
The US Geological Survey recorded at least 20 aftershocks of magnitude 4.0 or greater during the hours following the quake.
According to Rodrigo Soberanes, who lives in Chiapas, "the house moved like chewing gum."
Luis Carlos Briceno, a 31-year-old architect who was visiting Mexico City at the time of the quake, said he "had never been anywhere where the earth moved so much. At first I laughed, but when the lights went out I didn't know what to do. I nearly fell over."
At least sixty-one people died as a result of the earthquake.