A strong 7.9-magnitude earthquake on Wednesday night struck the center of Chile, American seismologists said, triggering a tsunami alert that stretched to Peru and the evacuation of coastal areas, according to the AFP news agency.
There were no immediate reports of injury or major damage, a government emergency agency said, but terrified residents rushed out onto the streets in Chile's capital Santiago and in Argentina.
The United States Geological Survey (USGS) put the shallow offshore quake at a magnitude of 7.9 and said it hit just 228 kilometers (about 140 miles) north of Santiago, according to AFP.
The quake had a depth of eight kilometers and hit at 7:54 p.m. local time (2254 GMT), USGS said, also reporting two aftershocks, both above 6.0.
The Chilean government, however, put the earthquake at 8.0 on the Richter scale.
Interior Minister Jorge Burgos said that the evacuation of coastal towns and cities was ordered as a precautionary measure.
The quake was felt as far away as Buenos Aires, in Argentina, about 1,400 kilometers away, while a tsunami warning was in place for the whole of Chile and Peru's Pacific coastline.
In Santiago, a city of 6.6 million people, thousands fled swaying buildings, an AFP reporter said.
The Hawaii-based Pacific Tsunami Warning Center said that "hazardous" tsunami waves were possible for some coasts, including above three meters (10 feet) the tide level along parts of Chile's shoreline.
Tsunami waves were also possible along French Polynesia, it said, as well as smaller waves as far afield as Japan and New Zealand.
In April of last year, an 8.2-magnitude earthquake in northern Chile killed six people and forced a million to leave their homes in the region around Iquique.
A February 27, 2010 quake that struck just off the coast of Chile's Maule region measured 8.8 in magnitude, killing more than 500 people and inflicting an estimated $30 billion in damages.