LONDON (REUTERS) - A magnitude 6.6 offshore earthquake struck the Indonesian archipelago late on Friday (Aug 17), the US Geological Survey said.

The quake was located 153 km north-east of the city of Raba, located on the island of Sumbawa, at a depth of 564.7 km, it said.

There was no immediate report of a tsunami threat.

(This story is developing.)