A powerful 6.5-magnitude earthquake struck eastern Indonesia on Friday, but no tsunami warning was immediately issued, US seismologists said.

The earthquake hit at 5:02 pm local time, the US Geological Survey said, and was centred three kilometres east- southeast of Andekanter in the Sumba region at a depth of 30 kilometres. The Indonesian disaster mitigation agency said there were no immediate reports of damage or casualties.

"Currently our teams are still checking whether there have been any damages or casualties," the agency spokesman Sutopo Purwo Nugroho told AFP. Indonesia sits on the Pacific "Ring of Fire" where tectonic plates collide, causing frequent seismic and volcanic activity in the region.

A 6.9-magnitude quake that struck in the Banda Sea in December sparked panic but there were no reports of damage or casualties.