JAKARTA - A MODERATE 5.1-magnitude earthquake struck off Indonesia's Papua region on Thursday, seismologists said, but there were no immediate reports of casualties or damage.

The quake, which hit at 4.03pm (3.03pm Singapore time), was centred 201 kilometres north-west of the Papuan provincial capital of Jayapura at a depth of 35km, the US Geological Survey said.

No tsunami warning was issued.

The Indonesian archipelago sits on the so-called Pacific Ring of Fire where continental plates meet, causing frequent seismic and volcanic activity. -- AFP