Two strong earthquakes rocked Indonesia's eastern province of Maluku on Sunday, but there were no immediate reports of damage or casualties, the local geological agency said.

The first quake of magnitude-6.4 struck just about 40 minutes after midnight; the second, measuring 6.0 magnitude, came at 7:40 a.m., said Benny Sipollo of the Meteorology and Geophysics Agency office in Ambon.

Both quakes were centered under the Banda Sea (search), just over 150 miles northwest of Ambon, about 140 miles beneath the earth's surface.

Ambon, about 1,600 miles east of Jakarta (search), is the capital of the archipelagic province of Maluku.

A quake of magnitude 6 can cause considerable damage if centered near residential areas.

Indonesia, the world's largest archipelago nation, is prone to seismic upheavals due to its location on the so-called Pacific "Ring of Fire."

On Friday, a magnitude-5.9 quake hit near Banda Aceh, the capital of the Aceh Province, which was ravaged by the Dec. 26 earthquake and tsunami that killed at least 174,000 in the Indian Ocean basin.