Over 100 police officers were sent to Papua after unknown gunmen shot dead 3 police officers on Tuesday, Indonesian National Police chief General Timur Pradopo said.

Investigation into the shooting is underway, said Pradopo.

One of the dead officers was the district police chief.

Another officer was reported missing after the attack at 5 am local time.

Local separatist group of Free Papua Movement has targeted soldiers, policemen and those working for giant US gold miner Freeport McMorant in Papua.