The quake's epicenter was located 171 kilometers southeast of the Philippine city of General Santos, home to about 679,000 people, TASS reports.
The earthquake occurred at a depth of 91 kilometers.
In the past 24 hours, Indonesia has had 50 quakes of magnitudes above 2 and up to 6.8.
Indonesia, an archipelagic nation, has been frequently hit off by earthquakes for its position on a vulnerable quake-jolted area called "the Pacific Ring of Fire."
SD/PR