The epicentre of the quake was several hundred kilometres off the southern coasts of Chile and Argentina, according to the United States Geological Survey.
Chile has issued a tsunami warning after a 7.4-magnitude earthquake struck off its southern coast on Friday.
The epicentre was under the sea 219km south of the Argentinian border town of Ushuaia, according to the United States Geological Survey (USGS).
Chilean authorities issued an evacuation order for the entire coast in the Magallanes region, which lies in the south of the country.
Chile's National Service for Disaster Prevention and Response also requested that people abandon all beach areas in the Chilean Antarctic territory.
Chilean President Gabriel Boric wrote on X that "all resources are available" to respond to potential emergencies.
"We are calling for the evacuation of the coastline throughout the Magallanes region," he wrote. "Right now, our duty is to be prepared and heed the authorities."
Images broadcast on local television showed residents in Punta Arenas, located on the Strait of Magellan, out in the streets searching for shelters.
"We received the alert and we had to evacuate at work, but people are calm and well prepared," Roberto Ramírez told a local news channel.
Local authorities in Argentina's Ushuaia, the world's southernmost city, suspended all water activities in the Beagle Channel for at least three hours.
"The earthquake was felt primarily in the city of Ushuaia and, to a lesser extent, in towns across the province," the local government reported.
"In the face of these types of events, it is important to remain calm," it added.
There were no immediate reports of damage or casualties in either Argentina or Chile.