An earthquake measuring a magnitude of 6.2 hit Indonesia's Sumatra Island on Saturday morning, but there have been no immediate reports of damage or casualties, the U.S. Geological Survey said.

The U.S. agency said the temblor, which occurred at 8:44 a.m., was centered near the town of Sibolga in North Sumatra Province, about 1,335 kilometers northwest of Jakarta. The focus was 35 km under the seabed.

Indonesia, with more than 17,000 islands, is prone to earthquakes.