Indonesia ? A strong earthquake struck off the coast of the Indonesian island of Sumatra on Saturday, but no damage or injuries were reported.

The magnitude 6 temblor was centered off the coast of northern Sumatra, about 60 miles west-southwest of Banda Aceh, the Hong Kong Observatory said today in a statement.

Residents in Banda Aceh, the capital of Aceh province, said they did not feel the quake.

Hours earlier, the nearby island of Nias was hit by two earthquakes of magnitude 5 and 5.2 that occurred within minutes of each other, according to the U.S. Geological Survey. Indonesian authorities said some residents were panicked but there were no injuries.

Indonesia repeatedly has been rocked by quakes since the massive temblor on Dec. 26 that produced a deadly tsunami. The Indian Ocean disaster killed more than 176,000 people in 11 countries and left about 50,000 missing and hundreds of thousands homeless.