The IMB did not reveal the name of the vessel.
In a statement the watchdog said, “Five gunmen fired several shots at the tanker before stealing unspecified equipment.”
“No one was injured in the attack Monday on the tanker moored at Anyer port on the western tip of Java Island,” added the IMB without elaborating further.
The Indonesian authorities have released a statement stating they received no report of an incident of the sort.
Indonesia has already suffered 50 pirate attacks for the first half of this year and this figure does not include the 20 attacks on vessels plying through the Straits of Malacca so far this year.