SAN MARCOS, Guatemala — A 7.4-magnitude earthquake struck off the Pacific coast of Guatemala Wednesday morning, killing up to 15 people according to preliminary reports from the country’s president.

President Otto Perez Molina told a news conference that not all deaths had been confirmed, but others reported people buried in some of the 30 houses that collapsed in the town of San Marcos near the northwestern border with Mexico, where most of the damage was reported.

Ovidio Perez, spokesman for the fire department in San Cristobal Cochu in the state of San Marcos, told the radio station Emisoras Unidas that 10 people, including a 4-year old, were buried. At least a dozen were reported injured in the same area.

The magnitude-7.4 quake, about 20 miles deep, was centered about 15 miles off the coastal town of Champerico and about 100 miles southwest of Guatemala City, shaking buildings as far away as Mexico City and El Salvador.

Survivors by radio and social media talked of widespread landslides and people trapped. But the accounts of deaths and people trapped were difficult to independently confirm as communication and roads were cut off to the area believed most affected, the mountainous state of San Marcos on the northwest border with Mexico.

It was the largest earthquake since a 1976 temblor killed 23,000 in the small Central American country.

“I’ve been in Guatemala for almost two years I am used to earthquakes. This was a lot more severe, a lot more shaky,” said Peace Corps volunteer Adam Baker, 27, of Carmel, Ind., who tweeted a picture of a small landslide behind his house in the nearby state of Quetzaltenango. “Things fell in my kitchen.”

Nicaragua’s disaster management agency said it had issued a local tsunami alert, but there were no immediate reports of a tsunami on the country’s Pacific coast.

People fled buildings in Guatemala City, in Mexico City and in the capital of the Mexican state of Chiapas, across the border from Guatemala.

A reporter in San Marcos, a mountainous, mostly rural region about 80 miles north of the epicenter, told local radio station Emisoras Unidas that houses had collapsed onto residents and smashed televisions and other appliances had been scattered into the streets of the main town.

The local fire department said on its Twitter account that a school had collapsed and eight injured people had been taken to a nearby hospital. Local radio reported widespread power outages and cuts in telephone service.

Molina said in a radio interview that the country of 14 million had been placed on its highest level of disaster alert and he asked people to evacuate tall buildings as an emergency measure.

A spokesman for El Salvador’s Red Cross branch told The Associated Press that the quake had been felt throughout the country, sending people fleeing their homes in the capital, but there had been no immediate reports of injuries or serious damage. He said there had been no local tsunami warning issued. El Salvador’s Civil Protection agency said officials were evacuating some coastal communities as a precautionary measure.

The mayor of Mexico City said no serious damage or injuries had been reported in the city, although many people had fled their offices and homes during the quake.