LONDON/DUBAI • An Iranian Revolutionary Guards commander threatened yesterday to seize a British ship in retaliation for the capture of an Iranian supertanker in Gibraltar by the Royal Marines.
"If Britain does not release the Iranian oil tanker, it is the authorities' duty to seize a British oil tanker," Mr Mohsen Rezai said on Twitter.
The Gibraltar government said crew members on board the supertanker Grace 1 were being interviewed as witnesses, not criminal suspects, in an effort to establish the nature of the cargo and its ultimate destination.
In a statement yesterday, it said it had acted to detain the tanker, suspected of carrying oil to Syria in violation of sanctions, of its own accord and not on any other government's order.
British Royal Marines on Thursday abseiled onto the ship off the coast of the British territory and seized it. They landed a helicopter on the moving vessel in pitch darkness.
The move escalates a confrontation between Iran and the West just weeks after the United States called off air strikes minutes before impact, and draws Washington's close ally into a crisis in which European powers have so far striven to appear neutral.
Teheran summoned the British ambassador on Thursday to voice "its very strong objection to the illegal and unacceptable seizure" of its ship, a move that also eliminated doubt about the ownership of the vessel. Foreign Ministry spokes-man Abbas Mousavi said the crude oil cargo was from Iran.
European countries have walked a careful line since last year, when the US ignored their pleas and pulled out of a pact between Iran and world powers that gave Teheran access to global trade in return for restrictions on its nuclear programme.
Over the past two months, Washington has sharply tightened sanctions against Teheran with the aim of halting its oil exports altogether. The moves have largely driven Iran from mainstream markets and forced it to find unconventional ways to sell crude.
The confrontation took on a military dimension in recent weeks, with Washington accusing Iran of attacking ships in the Gulf and Iran shooting down a US drone. US President Donald Trump ordered and then cancelled retaliatory strikes.
With nuclear diplomacy at the heart of the crisis, Iran announced this week that it had amassed more fissile material than allowed under its deal, and also said it would purify uranium to a higher degree than permitted from tomorrow.
The Grace 1 was impounded in the British territory on the southern tip of Spain after sailing the long way around Africa from the Middle East to the mouth of the Mediterranean.
Shipping experts say the vessel may have been avoiding the more direct route through the Suez Canal, where a big tanker would typically be required to unload part of its cargo, potentially exposing it to seizure.
Gibraltar said on Thursday that it had reasonable grounds to believe the Grace 1 was carrying crude oil to the Baniyas refinery in Syria. It made no mention of the ownership of the vessel or the origin of its cargo.
While the European Union has not followed the US in imposing broad sanctions against Iran, it has had measures in place since 2011 that prohibit the sale of oil to Syria.
A spokesman for the Gibraltar government said the 28-member crew, who have remained on board the supertanker, were mainly Indians, with some Pakistanis and Ukrainians.
REUTERS, AGENCE FRANCE-PRESSE