NATO has condemned Iran over its seizure of a British-flagged tanker in the Strait of Hormuz.

The western military alliance said the action represents a “clear challenge to international freedom of navigation.”

It said all its members “remain concerned by Iran's destabilising activities” and welcomed UK claims that it will attempt to address the situation through “dialogue and diplomacy.”

“We urge Iran to immediately release the ships and their crew,” it said in a statement.

“The UK has made clear that their priority is to address the situation through dialogue and diplomacy. NATO supports all diplomatic efforts to resolve this situation.”

Gibraltar

Iran originally said the Stena Impero tanker was held because it collided with an Iranian fishing boat and ignored its distress calls.

However, the country has since suggested the action was in response to the UKs seizure of an Iranian tanker off Gibraltar earlier this month.

A spokesperson for the country’s Guardian Council said "the rule of reciprocal action is well-known in international law."

Stena Bulk, the Swedish company that owns the ship, said the Head of Marine Affairs at the Iranian Port of Bandar Abbas has assured it that the crew are in ‘good health’ and arrangements are being made for it to visit with them.

File photo of the British HMS Montrose escorting another ship through the narrow Strait of Hormuz in February 2014. Image: UK Ministry of Defence

Iran Sanctions

The UK is reportedly planning a range of diplomatic and economic measures against Iran – including potential asset freezes – in response to the seizure.

Foreign Secretary Jeremy Hunt is expected to announce the measures in a statement to the Commons next week.

The country has written to the UN warning that the seizure “constitutes illegal interference,” and insisting the ship was in Omani territorial waters and was “exercising the lawful right of transit passage in an international strait.”

UK government should contain those domestic political forces who want to escalate existing tension between Iran and the UK well beyond the issue of ships. This is quite dangerous and unwise at a sensitive time in the region. Iran however is firm and ready for different scenarios.

— Hamid Baeidinejad (@baeidinejad) July 21, 2019

This morning, Iran's ambassador to the UK waded said Tehran is “firm and ready for different scenarios.”

Hamid Baeidinejad tweeted: "UK government should contain those domestic political forces who want to escalate existing tension between Iran and the UK well beyond the issue of ships.

"This is quite dangerous and unwise at a sensitive time in the region. Iran however is firm and ready for different scenarios."

Restraint

Labour leader Jeremy Corbyn has called for the tanker and its crew to be released – but said all sides must show restraint as escalation risks a “deeper conflict.”

The European Union has warned the development “brings risks of further escalation.”