An AFP reporter in Port Blair, the main town on the islands, said the quake sent people running from their homes and disrupted telephone and electricity supplies.

However there was no sign or reports of injuries or damage.

The USGS said the epicentre of the quake, which hit at 0820 GMT (3.20pm Singapore time), was 120 kilometres southwest of Port Blair.

The Pacific Tsunami Warning Centre did not issue an alert after the quake, which struck at a depth of 10 kilometres.

Throughout the day a series of aftershocks hit the same area at the same shallow depth. -- AFP