WASHINGTON -- (UPDATE) A strong 6.1-magnitude earthquake struck far northern Argentina Saturday near its border with Chile and Bolivia, the US Geological Survey said.

The quake rattled part of the Andes mountains region at 4:44 pm (1944 GMT), some 190 kilometers (120 miles) northwest of San Salvador de Jujuy and 240 km (150 miles) southwest of Tarija, Bolivia at a depth of 141 km (88 miles), according to the USGS.

There were no immediate reports of casualties or damage.

The tremor followed two substantial quakes in the region Friday, including one of magnitude 6.5 near the Chile-Peru border and another measuring 5.8 that struck several hundred kilometers to the north of Argentina's Jujuy province.

The readings are based on the open-ended Moment Magnitude scale, now used by US seismologists, which measures the area of the fault that ruptured and the total energy released.

Earthquakes are common in the western part of South America, along which runs the Peru-Chile trench, a region home to the seismically active Pacific Ring of Fire.