It’s becoming more of a chess game. Disagreement on the nuclear issue between the United States and Iran is pushing a clash on the military-strategic level.

After Iran’s Revolutionary Guard shot down a US drone 20 June, local port and law enforcement agencies — backed by the British Royal Marines — captured a huge Iranian oil tanker in Gibraltar Thursday.

However, aside from aggressive statements, the Iranian reaction will depend on how good a nuclear settlement with the Trump administration would be.

The chief minister of Gibraltar — which has been ruled by Britain since 1713 — Fabian Picardo said, “we have reason to believe that Grace I was carrying its shipment of crude oil to the Baniyas Refinery in Syria,” adding that the “refinery is the property of an entity that is subject to European Union sanctions against Syria”.

One day later, 5 July, the Supreme Court in Gibraltar added 14 more days to the detention of the tanker that has a carrying capacity of 300,000 tons, according to information provided by the Iranian state news agency (IRNA).

This is an issue with roots. In 2011, the European Union (EU) banned all imports of oil to Syria, responding to then six months of violent suppression of the anti-Bashar Al-Assad uprising.

The EU also banned European businessmen from getting involved in economic activities with Al-Assad, his aides and top-level Syrian officials. The United States also took similar action at this time.

The Syrians have not commented on the capture of the Iranian tanker. The Americans praised the British action. John Bolton, Trump’s national security adviser, said on Twitter it was “excellent news”.

“UK has detained the supertanker Grace I laden with Iranian oil bound for Syria in violation of EU sanctions. America & our allies will continue to prevent regimes in Tehran & Damascus from profiting off this illicit trade,” tweeted Bolton.

Iran, which has been diplomatically, militarily and economically backing Al-Assad’s regime for years, is clearly angry. Iran summoned the British ambassador to Tehran, and Iranian Foreign Ministry Spokesman Abbas Mousavi described the incident as a “form of piracy”.

He stressed that the move indicated that “the UK follows the hostile policies of the US, which is unacceptable for the Iranian nation and government.”

Mohsen Rezaei, head of Iran’s Expediency Council, which offers policy recommendations to Supreme Leader Ayatollah Ali Khamenei, tweeted that “If Britain does not release the Iranian oil tanker, it is the [Iranian] authorities’ duty to seize a British oil tanker.”

There is no doubt that the nuclear crisis is catalysing this escalation. Iran declared Sunday that it surpassed the 3.67 per cent threshold of enriching uranium stipulated in the 2015 nuclear deal that Trump withdrew from in May 2018, reaching 4.5 per cent. Iran’s Atomic Energy Organisation warned that Tehran will go for 20 per cent if parties to the so-called Joint Comprehensive Plan of Action (JCPOA) did not support the country benefiting from the economic gains of the deal.

Trump, who imposed new sanctions on Iranian persons, entities and businesses, called on Iran to “be careful”. “Because you enrich for one reason, and I won’t tell you what the reason is. But it’s no good; they better be careful,” said Trump in New Jersey.

In terms of a retaliatory seizure of a British-owned or flagged vessel in Iranian waters, Maysam Behravesh — senior political analyst at Persis Media, a US-based production firm —pointed out that “Iran is unlikely to take further provocative actions at the moment” despite tensions “running very high now” between Tehran and European powers, who are struggling to salvage the nuclear deal.

“Tehran will likely try to use the Gibraltar incident as a source of political leverage to increase pressure on the EU and compel it to shield its interests against American sanctions. But if push comes to shove, so to speak, and European powers reinstate sanctions against the Islamic Republic, much like the United States did last year, then retaliatory seizure of a British-affiliated tanker or other punitive response of international significance, might very well be on the cards,” he said.

Behravesh also argued that Britain is trying to get closer to the US and its regional Arab allies as it is in the “throes of leaving the European Union”.

He explained that Britain’s decision to detain Grace I — on the grounds that it was carrying two million barrels of Iranian crude to Syria, in violation of EU and US sanctions — was made at the “behest of the United States”.

“This was a signal to the Iranian leadership that Europe is willing and ready to overlook its differences with the US and join its pursuit of a “maximum pressure” campaign against Iran if Tehran carries through on its threats of nuclear escalation,” said Behravesh, urging “some carrots rather than just sticks to persuade Iran back into compliance”.

Some reports were circulated on social media about stopping Pacific Voyager, a supertanker carrying a British flag, in the Gulf Saturday. But Iran said this was “fabricated” news.

An official at the UK Maritime Trade Operations (UKMTO) told Reuters that it stopped “as part of a routine procedure to adjust its arrival time at its next port”.

 *A version of this article appears in print in the 11 July, 2019 edition of Al-Ahram Weekly under the headline: From tankers to nukes