An Iranian former commander has said the country should seize a British oil tanker unless an Iranian ship detained by the Royal Marines is released.

The country’s former Revolutionary Guards commander Mohsen Rezaee said on Friday on Twitter that Iran’s “duty” was to act alike, and seize a British oil tanker, unless Iran’s ship was released immediately.

British Royal Marines detained an oil tanker in Gibraltar suspected of carrying oil to Syria in violation of EU sanctions on Thursday – a dramatic step that could escalate confrontation between the West and Iran.

The Royal Marines abseiled onto the Grace 1 tanker on Thursday and landed a helicopter on the moving vessel in pitch darkness.

Tehran has already summoned the British ambassador to voice “its very strong objection to the illegal and unacceptable seizure” of its ship.

Tensions high as Trump approves new Iran sanctions: In pictures Show all 17 1 /17 Tensions high as Trump approves new Iran sanctions: In pictures Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, their surface-to-air missile is seen as it shoots down a US surveillance drone EPA Tensions high as Trump approves new Iran sanctions: In pictures This photo shows US RQ-4A Global Hawk unmanned surveillance drone. A drone of this model was shot down by Iran on Thursday 21 June AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures An oil tanker is on fire after it was subject to a suspected attacked at the Gulf of Oman on June 13. The US has blamed Iran for the attack Reuters Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, debris from the downed US drone is seen after it was recovered from Iranian waters AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures US President Trump holds up a signed executive order to increase sanctions on Iran on 24 June AP Tensions high as Trump approves new Iran sanctions: In pictures Iranian President Rouhani stated in a televised address that the White House is "afflicted by mental retardation" following the increase in sanctions on 25 June EPA Tensions high as Trump approves new Iran sanctions: In pictures An Iranian navy boat tackles the fire on the Norwegian owned Front Altair oil tanker after it was hit in a suspected attack AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, debris from the downed US drone is seen after it was recovered from Iranian waters AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures A screenshot from a video released by the US Department of Defense that the US claims to show Iranian removing an unexploded limpet mine form the hull of the Japan-owned ship that was attacked in the Gulf of Oman on June 13 Getty Tensions high as Trump approves new Iran sanctions: In pictures An item reportedly found on the Japan-owned oil tanker that was attacked on June 13 in the Gulf of Oman AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures A handout photograph from the US Department of Defense shows a composite material that the US claim was left behind on the hull of the Japan-owned oil tanker following the removal of an unexploded limpet mine Getty Tensions high as Trump approves new Iran sanctions: In pictures A view from the cabin of an Iranian navy boat as it tackles the fire on the Norwegian owned Front Altair oil tanker after it was hit in a suspected attack EPA Tensions high as Trump approves new Iran sanctions: In pictures Release by US government A picture released by U.S. Central Command shows damage to the hull of the oil tanker Kokuka Courageous. The picture suggests that the ship is 'likely' to have been hit by a mine as the US Secretary of State Mike Pompeo moves to blame Iran for the suspected attack Reuters Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures Release by US government A picture released by U.S. Central Command shows damage to the hull of the oil tanker Kokuka Courageous. The pictures suggests that the ship is 'likely' to have been hit by a mine as the US Secretary of State Mike Pompeo moves to blame Iran for the suspected attack EPA

The country has also accused Britain of acting at the bidding of the United States.

But on Friday tensions rose as Mr Razaee wrote: “If Britain does not release the Iranian oil tanker, it is the (Iranian) authorities duty to seize a British oil tanker.”

“Islamic Iran in its 40-year history has never initiated hostilities in any battles but has also never hesitated in responding to bullies,” he added.

One senior Iranian lawmaker, reformist Mostafa Kavakebian, said the seizure “proves once again Britain’s lack of honour in obeying America” and puts the lie to “the Europeans’ empty claim that they’re looking to preserve the nuclear deal.”

Mr Kavakebian heads the Iran-UK parliamentary friendship group.

The 28-person crew on the enormous Iranian tanker are being interviewed as witnesses, not criminal suspects, authorities in Gibraltar said.

The territory’s police and customs officials have remained on board the ship to carry out their investigation, but the Royal Marines are no longer present, Reuters reports.

On Thursday Gibraltar said it had reasonable grounds to believe the Grace 1 was carrying crude oil to the Baniyas refinery in Syria.

The EU imposed sanctions on the country in 2011 after Bashar al-Assad‘s crackdown on pro-democracy demonstrators spiralled into civil war.

Prime minister Theresa May’s official spokesperson said: “We welcome this firm action to enforce EU sanctions against the Syrian regime and commend the Gibraltarian authorities involved in successfully carrying out this morning’s operation.

“This sends a clear message that violation of the sanctions is unacceptable.”

The Foreign Office also welcomed the “firm action” by the Gibraltarian authorities.

The clash is another of the consequences of unilateral US sanctions on Iran. Unable to sell its oil through global energy companies worried about drawing the ire of Washington, Iran is forced into making clandestine deals beyond the surveillance of US authorities.

The US has been criticised for using its economic might to stretch the limits of international law and norms.

By enforcing EU sanctions against a non-EU member, the UK appears to be using a similar approach. No such steps have been taken by the UK or other EU nations against Russian vessels exporting energy and weapons to Syria.

Spain’s acting Foreign Minister, Josep Borrell, said on Thursday that the action was undertaken following “a demand from the US to the UK,” even as London tried to depict the move as one requested by Gibraltar.