A strong earthquake was reported in the ocean off Indonesia on Sunday, the U.S. Geological Survey said.

The quake measured a magnitude of 6.7, the survey reported. It hit at 3:41 a.m. local time (1941 GMT)

It struck at a depth of 11 miles (17.7 kilometers) and had its epicenter about 10 miles (15 kilometers) north-northwest of Sumbawa and 830 miles (1,335 kilometers) east of the Indonesian capital of Jakarta.

There were no immediate reports that tsunami warnings were issued and no immediate reports of damage.

Over 300 buildings were seriously damaged and over 3,000 people escaped from their homes after a 7.4-magnitude quake rocked North Sulawesi province on Thursday morning, according to the Health Ministry.

The quake damaged houses, religious centers, school buildings and hospitals, but no report of casualties, head of a crisis center of the Ministry Rustam Pakaya said.

A series of powerful earthquakes at dawn killed at least three people and injured dozens more in remote eastern Indonesia on Sunday, cutting power lines and badly damaging buildings.

A 7.6-magnitude quake struck at 4:43 a.m. local time (1943 GMT) about 85 miles (135 kilometers) from Manokwari, Papua, at a depth of 22 miles (35 kilometers), the U.S. Geological Agency said. It was followed by a strong 7.5 aftershock.

Three bodies were found including a 10-year-old girl, hospital director Hengky Tewu told The Associated Press.

Another tsunami-triggering earthquake off Indonesia is “extremely likely” in the next 30 years and may claim a higher toll than the 2004 surge that killed more than 220,000 people, according to a study in the journal Science.

Researchers studying changes over the past 700 years in coral reefs near Indonesia’s Mentawai islands found evidence the region is due for a quake as big as magnitude 8.8, and that a smaller temblor last year is probably a harbinger of bigger ones.

A large shock would set off a tsunami that would strike cities and towns in western Sumatra, scientists led by Kerry Sieh of the California Institute of Technology in Pasadena said in the study, to be published today.