The earthquake was shallow at a depth of 6.1 miles. (Representational)

A 6.8 magnitude earthquake struck in the Pacific off the coast of Chile on Sunday, the United States Geological Survey (USGS) said.

"There is a low likelihood of casualties and damage," the USGS said of the earthquake, which it earlier reported as a magnitude 7.2, and which occurred 41 miles (66 kilometers) west-southwest of Constitucion, Chile.

Chile's National Seismological Center (CSN) put the quake at 6.6 magnitude.

Despite the tremor's strength, there were no reports of injuries, impacts to basic services or damage to infrastructure, according to Chile's National Emergency Office (ONEMI).

There were also no tsunami warnings, advisories, watches or threats in the wake of the earthquake, according to the US Tsunami Warning System.

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

The 1960 Valdivia earthquake in Chile was, at 9.5, the strongest ever recorded on the magnitude scale, according to the USGS.

Chile lies on the Ring of Fire -- an arc of fault lines that circles the Pacific Basin and is prone to frequent earthquakes and volcanic eruptions.