A 6.6-magnitude earthquake, the fourth during the night, hit Chile in the early hours of Tuesday morning, a RIA Novosti correspondent reported.

The quake, with the epicenter in the small town of Cobquecura on the Pacific coast, struck at 5:45 a.m. local time [08:45 GMT].

It followed an earlier tremor that occurred at 02:22 GMT some 75 km (50 miles) north of the western Chilean city of Concepcion.

While there were no immediate reports on causalities, the Chilean government has issued a tsunami alert.

Some 150 tremors have been registered in Chile since an 8.8-magnitude earthquake occurred to the north of Concepcion in late February. According to official reports, 497 people died as a result of that tremor.

It was followed by a series of aftershocks and tsunamis leaving some 2 million Chileans homeless and damaging about 1.5 million buildings.

Chile's new president, Sebastian Pinera, has said it would cost at least $30 billion to rebuild the country after the devastating earthquake.

SANTIAGO, March 16 (RIA Novosti)