A month of escalation: how two tanker attacks in the Gulf unfolded

The Gulf region had been relatively untouched by the crisis between Tehran and Washington until last month

FILE - This May 13, 2019, file photo provided by the United Arab Emirates' National Media Council shows the Norwegian-flagged oil tanker MT Andrea Victory off the coast of Fujairah, United Arab Emirates. International investigators believe last month's attacks on oil tankers in a United Arab Emirates port were led by a foreign state using divers on speed boats who planted mines on the vessels. (United Arab Emirates National Media Council via AP, File)Show less

An apparent attack on two oil tankers in the Gulf of Oman on Thursday was the culmination of weeks of escalation in the region.

As tensions have risen between Tehran and Washington, the Gulf had been relatively untouched by the crisis. But that was until May 12, when four commercial vessels docked off the coast of the Emirati city of Fujairah were damaged in an incident blamed by the US on Iran or its regional proxies.

The attack took place in the UAE's territorial waters and Abu Dhabi confirmed the "sabotage attack" without pointing the finger at any one party.

A subsequent probe was established with the help of international allies of the UAE, including the US, Saudi Arabia, Norway and France. Iran decried the incident as a potential false flag operation to frame Tehran.

But it established that a sophisticated operation involving divers and limpet mines damaged the hulls of the ships, which were two Saudi-flagged vessels, one Norwegian and one Emirati ship.

A summary of the report's preliminary findings of the probe concluded that a "state actor" was most likely behind the operation.

“The four attacks were part of a sophisticated and coordinated operation carried out by an actor with significant operational capacity, most likely a state actor,” said a statement to the UN from the UAE, Saudi Arabia and Norway.

US National Security Adviser John Bolton accused Iran’s Revolutionary Guard of being behind the attack, but the initial findings of the UAE-led investigation did not name a specific state.

The report said the investigation would continue and that the three countries would share the preliminary findings with the International Maritime Organisation in London.

Just two days before the attack, the US said it would move a Patriot missile battery into the Middle East to counter Iranian threats.

The countries have not retaliated for the attack. But the escalation has only continued. Iranian-allied rebels in Yemen have increased their missile and drone attacks on Saudi Arabia, including a major oil pipeline and a commercial airport, which has been at war in Yemen against the rebels since 2015.

On Thursday, two oil tankers near the Strait of Hormuz were reportedly attacked. In all, 44 sailors were evacuated from the vessels and the US Navy has assisted amid heightened tensions between Washington and Tehran.

How the US and Iranian governments react to the event will be key. The United States has recently moved more military forces into the region, which already hosts the US Navy 5th Fleet in Bahrain and the forward headquarters of the U.S. military's Central Command at the vast Al-Udeid Air Base in Qatar.

Iran has set a July 7 deadline for Europe to find new terms for Tehran's nuclear deal with world powers. That accord began to unravel after the Trump administration unilaterally withdrew from the Obama-era deal and re-imposed US sanctions aimed at crippling the Iranian economy and pressuring a change in its regional policies. Iran has threatened it could resume higher levels of enrichment.

For now, there will be fears for shipping companies and the crews transporting their goods through the Strait of Hormuz and the Gulf of Oman after attacks on at least six vessels in just over a month.