The two vessels one flying the Malaysian flag and another the Thai flag are now detained in the navy base of Tarempa for further investigations, Lt. Col Ariris Miftachurrahman, the spokesman of the navys western fleet command, said on Saturday.
Ariris said the two vessels were caught on last Friday when the KRI Sutedi Senaputra-878 was patrolling that area where foreign fishing vessels have often been found illegally operating.
The two vessels were caught red handed illegally fishing in the Indonesian water territory, he said.
The vessel flying the Malaysian flag named MV.KNF 7424 had nine crewmen including six Thais, and three Burmese.
The other flying the Thai flag named MV. Kour Son 77 had six crewmen including two Thais, three Burmese and one Laotian.