Britain is seeking to put together a European-led maritime protection mission to protect shipping in the Gulf following the seizure of a British oil tanker by Iran, British Foreign Secretary Jeremy Hunt told the House of Commons on Monday.

Updating MPs about the crisis, Hunt announced the Department of Transport has raised the security level for British-flagged shipping, advising against all passage in Iranian waters and, for the moment, in the entire Strait of Hormuz.

Hunt told MPs: "If Iran continues on this dangerous path, they must accept the price will be a larger Western military presence in the waters along their coastline, not because we wish to increase tensions but simply because freedom of navigation is a principle which Britain and its allies will always defend."

"Freedom of navigation is a vital interest of every nation, the aim of the maritime protection mission will be to support safe passage of both crew and cargo in what is a vital region," he said.

Last Friday, Iran's Islamic Revolution Guard Corps (IRGC) seized the British oil tanker "Stena Impero" in the Strait of Hormuz for what it called "failing to respect the international maritime rules while passing through the strait."

Hunt urged Iran to release the Stena Impero and its crew.

Before the Stena Impero incident, the police of Gibraltar, which is seen by Britain as its overseas territory, had arrested the captain and chief officer of an Iranian oil supertanker Grace 1.

Gibraltar authorities intercepted the Iranian oil tanker on July 4 in the Strait of Gibraltar on alleged suspicion of transporting Iranian crude oil to Syria, in violation of European Union's sanctions against Syria.

In a separate development that could generate more tensions, Iran said it had arrested 17 spies working for the CIA and sentenced some of them to death, an announcement Trump called “totally false.”

Iranian state television published images it said showed CIA officers who had been in touch with the suspected spies. The Ministry of Intelligence said the 17 spies had been arrested in the 12 months prior to March 2019.

Such announcements are not unusual in Iran and are often made for domestic consumption, although the timing suggests the possibility of an intention to link it to the Gulf crisis. 

Trump later told reporters it was getting harder for him to want to make a deal with Iran.

(Cover: British Foreign Secretary Jeremy Hunt arrives at 10 Downing Street for an emergency committee meeting in London, UK, July 22, 2019. /Xinhua Photo)