A 6.7-magnitude aftershock hit near Concepcion on Monday, the U.S. Geological Survey reported.

The aftershock struck off Chile's coast, some 86 km from Concepcion, one of the cities hardest hit by the 8.8-magnitude quake on Feb. 27. Its epicenter was 34 km deep in the Pacific Ocean.

The quake was strongly felt in Concepcion and caused a power blackout that plunged the city into darkness.

Authorities have not issued a tsunami warning.