JAKARTA, June 25 (Xinhua) -- An earthquake measuring 5.6 magnitude on the Richter scale jolted western parts of Indonesia Wednesday morning, but there were no immediate reports of damage or casualties, local Meteorology and Geophysics Agency said.

    The quake struck at 08:52 Jakarta time (0152 GMT) with epicenter at 42 kilometers southwest Gunungsitoli of North Sumatraprovince and 12 kilometers in depth, an official of the agency said.

    Indonesia sits at a vulnerable zone, so called "the Pacific Ring of Fire", where two continental plates meet that causes frequent volcanic movements.