DUBAI, United Arab Emirates (AP) – In an audio recording released by a maritime security risk firm, a British naval officer can be heard saying that the transit of a British-flagged vessel through the Strait of Hormuz must not be impaired under international law, just before it is seized by Iranian forces.

The same recording has an Iranian naval officer telling the Stena Impero to change course, saying: “You obey, you will be safe.”

The audio released Sunday by Dryad Global shows how the British navy was unable to prevent the ship’s seizure by Iranian forces on Friday.

Iranian officials say the move came in response to Britain’s role in seizing an Iranian supertanker loaded with some 2 million barrels of crude weeks earlier.

Friday’s incident comes amid heightened tensions between the U.S. and Iran.