Iran on Friday denied it owned the cargo on one of its flagged tankers that was seized following a suspected illicit ship-to-ship (STS) transfer off the coast of Indonesia.

The 300,600-dwt Arman 114 (built 1997), carrying 2m barrels of crude, was held after it was spotted in the North Natuna Sea carrying out an STS operation without the authorities having been notified, according to Indonesia’s maritime security agency Bakamla.

“Any reports attributing the cargo of the vessel to the Islamic Republic of Iran lacks any validity,” Iran’s oil ministry said in a statement, according to the Tehran Times.

The ministry said any reports were intended to “create a negative atmosphere in our country” but did not offer an alternative explanation.

The tanker was boarded by armed Bakamla officials this month while Malaysian marines descended onto its deck by rope from a helicopter. The Egyptian captain and 28 Syrian crew members were detained.

Bakamla said the Arman 114 and the second ship, identified by tanker trackers as the 306,100-dwt Lilu (built 2000), had tried to escape with transfer equipment still attached. The vessels did not respond to communications.

The registered owner and manager of the Arman 114, listed as Panama-based Ocean Mark Shipping, could not be contacted for comment.

Under the International Convention for the Prevention of Pollution from Ships (Marpol), tanker operators should inform a state no less than 48 hours before a planned STS in its territorial waters or exclusive economic zone, which stretches 200 nautical miles (370 km) from the coast.