The Nigerian navy said in a statement that the Heroic Idun, a very large crude carrier (VLCC), was attempting to load oil at the Akpo SBM on Aug. 8 without due clearance from state oil company NNPC, and that it "resisted arrest" when ordered to stop.
Equatorial Guinea's ruling party said on Twitter its navy intercepted the ship and 25 crew on Aug. 13 for infractions "such as sailing without any identifying flag, fleeing from the Nigerian navy due to lack of documentation and consequently sailing in Equatorial Guinean waters without prior authorization."
It was not immediately clear who was the vessel's owner or operator. The navy named Norway's Hunter Tankers as the owner, but the firm sold it in July and did not respond to a Reuters query about the buyer.
A spokesperson for oil major BP said it initially chartered the Heroic Idun on a spot basis to load Akpo crude on Aug. 17-18, but ultimately chartered a different ship as it was "aware that she is unable to perform the lifting." The spokesperson said the company had no information or comment on what happened to the Heroic Idun.
Eikon ship tracking showed the tanker anchored at Luba, Equatorial Guinea.
In its statement, Equatorial Guinea said it had authorized Nigerian intelligence to participate in its investigations and said it would "officially hand over the ship to the Nigerian government."
The navy did not explicitly accuse the vessel of attempting to steal oil. But the detention comes as security services are on high alert to combat oil theft, which has decimated exports in what is typically Africa's largest producer, costing an estimated $1 billion in lost revenue in the first quarter alone.
Most stolen oil is siphoned from onshore pipelines, and theft from a marine export line in a large vessel would be notably rare.
