SANTIAGO - An earthquake measuring 6.3 on the moment magnitude scale rocked northern Chile and parts of southern Peru early Monday, the US Geological Survey said, as Chilean officials added there were no reports of casualties or damage.

"It was a medium intensity earthquake," the head of Chile's national emergency bureau, Carmen Fernandez, told a Santiago radio station.

She said local officials had measured the quake as 6.0 on the Mercali scale in the port of Iquique, some 2,000 kilometers (1,200 miles) north of Santiago.

US seismologists revised downwards the temblor's strength to 6.3, after earlier reporting it was at 6.6.

The quake hit some 40 kilometers (25 miles), east-northeast of Iquique, in the Tarapaca region close to the Peruvian border and was at a depth of 35 kilometers (21 miles), the USGS added.

Earthquake-prone Chile and Peru lie along the Pacific rim of fire and are regularly rocked by temblors, but damage is often limited as the desert region straddling their shared border is sparsely populated.

Peru's southwest coast was struck by a massive 8.0-moment magnitude earthquake in August that left more than 500 people dead.

Several quakes have rattled Chile in recent months, including a deadly 7.7-magnitude earthquake on November 14 that killed two people, injured 15,000, and damaged an estimated 4,000 buildings.

That quake hit the desert region of Antofagasta.

US geologists use the moment magnitude scale, which measures the area of the fault that ruptured and the total energy released.

In Peru the earthquake was felt in the country's south not far from the Chilean border, with minor tremors felt in the regions of Tacna, Moquegua and Arepiqua.