A major 7.7-magnitude earthquake struck off the west coast of Indonesia on Monday, seismologists said, but there were no reports of damage or casualties and an earlier tsunami warning was lifted.

The undersea quake hit Indonesia's Kepulauan Mentawai region at 9:42 pm (1442 GMT) at a shallow depth of 20.6 kilometres (12.8 miles), the US Geological Survey said.

The area is 240 kilometres west of Bengkulu on Sumatra island and 280 kilometres south of Padang, an area popular with tourists.

The Indonesian Geophysics and Meteorology agency lifted an earlier tsunami warning.

The 7.7 earthquake was followed by powerful magnitude 6.1 and 6.2 aftershocks about five and eight hours later in the same area.

Residents reported shaking as far away as the West Sumatran provincial capital of Padang relating to the earlier quake, but fears of widespread damage eased a few hours later.

"There was shaking that went on for about three seconds or so. Residents panicked and ran to the hills but now they are starting to come down. There's no report of casualties or damage," Disaster Management Agency spokesman Priyadi Kardono told AFP.

The power and shallow depth of the earthquake prompted the US-based Pacific Tsunami Warning Center to issue a "tsunami watch" bulletin to guide local authorities on how to respond but that was later cancelled.

Indonesia sits on the Pacific "Ring of Fire," where the meeting of continental plates causes high volcanic and seismic activity, and the archipelago is frequently struck by powerful earthquakes.

A 7.1-magnitude quake off the north coast of Papua in June killed 17 people and left thousands homeless.

The 2004 Asian tsunami -- triggered by a 9.3-magnitude quake off Sumatra -- killed at least 168,000 people in Indonesia alone.

A 7.6-magnitude quake killed about 1,000 people in the port of Padang on September 30 last year.