The Iranian government is seeking information on why Indonesia has detained one of its VLCCs following allegations of an illegal oil transfer.
National Iranian Tanker Co (NITC)'s 317,400-dwt Horse (built 2008) and the Chinese-operated 306,000-dwt Freya (built 2000) were seized by the Indonesia coast guard.
Photographs released by Indonesia show them side by side off Kalimantan province on Sunday.
Iran said the Horse was detained over a "technical issue" and has asked Indonesia to explain the seizure.
Iran’s oil minister Bijan Zanganeh told reporters: "It was carrying oil ... the issue is being followed up by Iran."
The vessels were heading to a dock at Batam Island for further investigation on Tuesday, an Indonesia Coast Guard spokesman told Reuters.
Seafarers being questioned
Wisnu Pramandita said some of the 61 crew members remained on board the VLCCs, while others were being detained on coast guard ships for questioning.
"The ministry of foreign affairs has coordinated with the coast guard and obtained information that two motor tanker ships ... are suspected of violating the law," Indonesian foreign ministry spokesman Teuku Faizasyah said.
"Currently, further investigations are being carried out in order to obtain a more complete picture of the violations committed."
Indonesia has claimed the two tankers concealed their identity by not showing their national flags, turning off AIS and not responding to a radio call.
The Horse was allegedly transferring oil to the Freya. Oil was detected in the water around the Freya, Indonesian authorities said.
Former Ridgebury vessel
The Freya is managed by Shanghai Future Ship Management.
The vessel is the former Ridgebury Purpose, sold last year by Ridgebury Tankers to Chinese interests.
Iran has previously been accused of concealing the destination of its oil by turning off AIS on its vessels.
The Horse delivered 2.1m barrels of Iranian condensate to Venezuela last year.
The ship was identified in 2020 by Venezuelan oil company PDVSA as the Master Honey, which does not show up in any shipping databases.
