A magnitude-6.8 earthquake shook buildings and broke some windows in north-central Chile on Wednesday, but officials discounted the possibility of a tsunami and reported no major damages.

The U.S. Geological Survey originally reported the quake at 6.7, but later revised it upward. It struck at 4:15 p.m. (3:15 p.m.; 2015 GMT) and was centered 27 miles (44 kilometers) north of Vallenar, Chile.

The quake shook the capital of Santiago, causing office buildings to sway, but was felt most powerfully in the north where state television showed images of scattered groceries at supermarket floors and broken windows at several homes in Vallenar, Copiapo and other nearby cities.

Witnesses described people running from buildings into the streets in panic.

Vallenar Mayor Cristian Tapia said telephone lines were jammed and some electricity lines were temporarily down but services were slowly returning.

"The first half hour was really tough. We're still having problems with telecommunications," Tapia told state TV. "Two walls collapsed. We're evaluating ruptures at homes to find out if they're still safe to live in."

But Chile's Emergency Office, ONEMI, said no injuries have been reported and damages to infrastructure appear minimal. The oceanographic service discounted the possibility of a tsunami.

"There's no doubt the population in some places fled, following a culture of evacuation," Miguel Ortiz, national chief of the early alert center at ONEMI. Two lower intensity aftershocks were also reported.

A devastating 8.8-magnitude quake and the tsunami it unleashed in 2010, killed 551 people, destroyed 220,000 homes and washed away docks, riverfronts and seaside resorts. The disaster cost Chile $30 billion, or 18 percent of its annual gross domestic product.

Chile is one of the most earthquake-prone countries in the world.

Just off Chile's long coast, the Nazca tectonic plate plunges beneath the continent, pushing the Andes to ever-higher altitudes. The 2010 quake was so strong it changed time, shortening the Earth's day slightly by changing the planet's rotation.

The strongest earthquake ever recorded also happened in Chile, a magnitude-9.5 in 1960 that killed more than 5,000 people.