Iran’s reckless behaviour risks triggering a “disastrous” escalation of hostilities in the Middle East, the head of the British military has said.

Chief of the Defence Staff General Sir Nick Carter said Iran made a “big mistake” when it targeted the Mercer Street tanker, killing a Briton and a Romanian.

The drone attack on July 29 off the coast of Oman led to international condemnation of Iran after the UK, US and Israel pinned the blame on Tehran.

They made a big mistake on the attack they did against the Mercer Street vessel last week because, of course, that has very much internationalised the state of play in the Gulf

Gen Carter told BBC Radio 4’s Today programme: “What we need to be doing, fundamentally, is calling out Iran for its very reckless behaviour.

“They made a big mistake on the attack they did against the Mercer Street vessel last week because, of course, that has very much internationalised the state of play in the Gulf.”

He added: “Ultimately, we have got to restore deterrence because it is behaviour like that which leads to escalation, and that could very easily lead to miscalculation and that would be very disastrous for all the peoples of the Gulf and the international community.”

Gen Carter’s comments came shortly after another incident in the waters around Oman.

Hijackers were believed to have seized a vessel off the coast of the United Arab Emirates in the Gulf of Oman.

They subsequently appeared to have left the ship, with the Royal Navy’s United Kingdom Maritime Trade Operations (UKMTO) organisation reporting that the incident, which it had described as a “potential hijack” was “complete”.

“The vessel is safe,” the group said, without identifying the ship.

Shipping authority Lloyd’s List and maritime intelligence firm Dryad Global had identified the hijacked vessel as Panama-flagged asphalt tanker Asphalt Princess.

Satellite-tracking data for the Asphalt Princess had showed it gradually heading towards Iranian waters early on Wednesday.

But it stopped and changed course back towards Oman, just before the UKMTO made its statement.

Over the past few years, commercial shipping in vital Persian Gulf waterways has increasingly been targeted, amid continued tensions between Iran and the West over its activities in the Middle East and Tehran’s fragile nuclear deal.

Apparently responding to Tuesday’s ship seizure, Iranian foreign ministry spokesman Saeed Khatibzadeh described recent maritime attacks in the Persian Gulf as “completely suspicious” and denied that Tehran played any role.

The Gulf of Oman is near the Strait of Hormuz, the narrow mouth of the Persian Gulf through which a fifth of all oil passes.

Fujairah, on the UAE’s eastern coast, is a main port in the region for ships to take on new oil cargo, pick up supplies or trade out crew.

For the past two years, the waters off Fujairah have seen a series of explosions and hijackings.

Gen Carter said the UK will work with allies to decide the best way of providing protection to shipping in the region, but a return to a system of convoys escorted by warships “may not necessarily be the right method”.

Meanwhile, Foreign Secretary Dominic Raab said the UK, Romania and Liberia – whose flag the Mercer Street was sailing under – have written to the president of the UN Security Council to raise the issue.

“The Council must respond to Iran’s destabilising actions and lack of respect for international law,” Mr Raab said.