JAKARTA (Reuters) - An earthquake of 6.5 magnitude struck off Indonesia's Sulawesi island on Wednesday, the U.S. Geological Survey said (USGS), but there were no immediate reports of casualties or damage.

The quake struck 138 miles (220 km) south of the town of Manado, in the north of the Sulawesi, the USGS said.

(Writing by Robert Birsel; Editing by Jeremy Laurence)