efe-epaBy Marina Villén Tehran

Iranian authorities on Saturday launched an inquiry into the British-flagged oil tanker Stena Impero that was seized in the Strait of Hormuz over allegations of breaching maritime regulations, although its detention has a political motive.

Stena Impero and its 23 crew members are being held in the port of Bandar Abbas, the capital of the southern province of Hormuzgan, where it was taken after it was impounded by Iran’s Islamic Revolutionary Guard Corps (IRGC).

The seizure of the vessel has triggered a new diplomatic crisis between Iran and the United Kingdom, as well as a spike in tensions in the Persian Gulf region.

The cause of a collision between the tanker and a fishing boat are being investigated, director-general of the ports and maritime department of Hormuzgan, Allahmorad Afifipour said.

Stena Impero’s crew members will remain on board until the investigation is concluded, but they could be summoned by judicial authorities for “technical interviews,” Afifipour added.

The vessel was being held for turning off its GPS, entering the Strait via the southern route, which is supposed to be the way out, and not responding to warnings from the ports and maritime department, sources close to the case said, as cited by Iran's private Tasnim agency.

The crew includes 18 Indian sailors, including the captain, and five others from Russian, the Philippines and Latvia.

Stena Bulk, the owner of the ship, denied the vessel had not respected maritime regulations, adding that it had lost contact with the 30,000-ton tanker at around 3 pm GMT shortly after it received warnings that several ships and a helicopter were approaching.

Rhe tanker was intercepted by the Iranian navy while on its way to Saudi Arabia from United Arab Emirates.

Although Iranian authorities say it was being held on legal grounds, several officials said the seizure was an act of retaliation over the holding of the Iranian oil tanker, Grace 1, off Gibraltar a couple of weeks ago.

Mohsen Rezaee, the secretary of the powerful Expediency Discernment Council, said on Twitter Iran would not back down when it comes to “taking retaliatory measures,” even against the “Queen” of England.

"The Iranian government's correct measure to confront the illegitimate economic war and seizure of oil tankers is an instance of this rule and is based on international rights,"Abbas Ali Kadkhodaei, spokesman for Iran's Guardian Council said.

Iran’s Minister of Foreign Affairs Mohamad Javad Zarif said the United Kingdom needed to stop acting as an "accessory" to United States sanctions against his country.

“UK must cease being an accessory to economic terrorism of the US,” Zarif said on Twitter, alluding to Washington-imposed sanctions after the US withdrew from the 2015 nuclear deal.

“Unlike the piracy in the Strait of Gibraltar, our action in the Persian Gulf is to uphold int’l maritime rules,” Zarif added in his tweet. “It is IRAN that guarantees the security of the Persian Gulf and the Strait of Hormuz.”

On July 4, the British navy impounded Iranian tanker Grace 1 off Gibraltar over suspicions the vessel was transporting oil to Syria, which would constitute a violation of European Union sanctions.

Supreme Leader Ayatollah Ali Khamenei considered the incident an “act of maritime piracy,” warning that his country would respond at the right moment.

That moment, apparently, was Friday night in the Strait of Hormuz, a strategic maritime pass between Iran and Oman.

Iran had taken advantage of “the minimum violation” of the maritime rules by the vessel, which under different circumstances it would not otherwise have paid any attention to, according to political analyst Mohamad Marandi.

“It was a response to the seizure of the Iranian oil tanker by the United Kingdom in Gibraltar and, until its release, it is likely that the British will be retained and that others will be captured,” he told Efe.

From London, there were no signs of Grace 1 being released, while Foreign Secretary Jeremy Hunt warned of “serious consequences” if the situation was not resolved soon.

He accused Tehran of taking a dangerous path, but was relying on diplomatic efforts rather than a military option. EFE-EPA