Stena Impero, a British-flagged vessel owned by Stena Bulk, at an undisclosed location. Photograph:( Reuters )
On Saturday British foreign minister Jeremy Hunt said the Stena Impero was seized in Omani waters in clear contravention of international law and then forced to sail into Iran. Iran says the tanker was captured after it collided with a fishing boat
The seizure of a British flagged tanker by Iran is in "clear violation of international law" because it was in Omani waters, the head of the UK Chamber of Shipping said on Sunday.
On Saturday British foreign minister Jeremy Hunt said the Stena Impero was seized in Omani waters in clear contravention of international law and then forced to sail into Iran. Iran says the tanker was captured after it collided with a fishing boat.
"The chart released by Her Majesty's government today clearly demonstrates that the Swedish-owned and British-flagged tanker, Stena Impero, was in Oman territorial waters when she was boarded by the Iranian Revolutionary Guard on Friday 19th July," said Bob Sanguinetti, CEO of the UK Chamber of Shipping.
"The evidence provided is proof that the seizing of the Stena Impero was in clear violation of international law."
Sanguinetti added that there is no comparison to be made with the seizure of Grace I, which was done under international law for the breach of EU sanctions.
"The Stena Impero was outside Iranian waters and legitimately carrying out its business at the time of its seizure," he said.
Iran's top diplomat said on Sunday that only "prudence and foresight" could alleviate tensions between his country and Britain after Tehran's seizure of a British-flagged oil tanker.
Watch: US-Iran tensions Soar after tanker seizure
Tehran for weeks has vowed to retaliate for the seizure of its Grace 1 oil tanker by British forces for violating European Union sanctions on Syria.
Britain needs to contain "those domestic political forces who want to escalate existing tension between Iran and the UK well beyond the issue of ships," Iran's envoy to Britain Hamid Baeidinejad said on Twitter.
"This is quite dangerous and unwise at a sensitive time in the region," he said, adding that Iran "is firm and ready for different scenarios."
Britain's junior defence minister Tobias Ellwood did not rule out the possibility of targeting Tehran with sanctions in response.
Tehran's seizure of the Stena Impero followed the July 4 capture by Royal Marines of the Grace 1 tanker carrying Iranian oil near Gibraltar.