Jakarta - A 6.1-magnitude earthquake struck Saturday morning in eastern Indonesia's Maluku islands, seismologists said.

The quake struck at 7:04 am Jakarta time (0004 GMT) at a depth of 72 kilometres, about 97 kilometres north-east of Ambon, capital of Maluku province, Indonesia's National Meteorological and Geophysics Agency (BMG) said.

An official at BMG office in Ambon, who identified himself only as Amien, said there were no immediate reports of injury and damage from the quake, which struck in the sea off the Seram Island of southern Maluku.

It was the second strong quake to hit the eastern Indonesian islands this week.

On Thursday, a powerful 7.6-magnitude earthquake struck off Halmahera Island in North Maluku province, triggering Indonesian authorities to issue a brief tsunami warning and sending people to running out of their homes in panic. But the quake caused no injury and damage.

Indonesia, the world's largest archipelago, sits on the Pacific "Ring of Fire," the edge of a tectonic plate prone to seismic upheaval.

A major earthquake and subsequent tsunami struck in December 2004, leaving more than 170,000 people dead or missing in Indonesia's Aceh province and half a million people homeless. (dpa)