JAKARTA - A 5.9-magnitude earthquake jolted off Indonesia's most densely-populated island of Java on Monday morning, the Indonesian Meteorological, Climatological and Geophysical Agency (BMKG) reported, but there have been no immediate reports of casualties or damage.

The quake struck at 9:13 am Jakarta time (0213 GMT) Monday. The epicenter was 112 km southeast of Malang Regency, East Java with a depth of 10 km under the sea. BMKG said there was no potential for tsunami.

The United States Geological Survey (USGS) put the magnitude at 5.8 with a depth of 77.3 km.

Indonesia sits on the so-called Pacific "Ring of Fire" where several tectonic plates meet, making it vulnerable to frequent earthquakes. More than 5,000 people were killed and massive infrastructure were damaged when strong quake struck off Java's Yogyakarta Province in 2006.