Limpet mines and drones are now on the minds of those tasked with plotting the course of world oil prices, as analysts continue to assess whether a military showdown between the US and Iran could be provoked.

Maritime security sources told Reuters on May 15 that images suggested damage to four vessels, including two Saudi oil tankers, caused in a sabotage operation in the Sea of Oman at the weekend was likely caused by limpet mines attached close to the waterline, in each case with less than four kilograms of explosives. The US has suggested Iran or Iranian proxies could have behind the attacks, while Tehran, categorically denying it was involved, says Israel, or foreign policy hawks in the US administration that want to spark a conflict, might have orchestrated the clandestine operation.

Meanwhile, Houthi militias backed by Iran in their fight against Saudi-supported forces in Yemen, claimed responsibility for a drone attack on oil pumping stations that forced Saudi Arabia to temporarily shut its main cross-country oil link on May 14.

The 1,200-km East-West pipeline carries crude from Saudi deposits to refineries and the port of Yanbu on the Red Sea coast to the west. It has a 5mn b/d capacity but Saudi Aramco transported 2.1 b/d of crude via the link last year. Saudi Arabia registers around 7mn b/d of crude sales, with most of that shipped from Persian Gulf ports along routes that go via the narrow Strait of Hormuz—which Iran has threatened to block should the US ever try to head off energy shipments that Tehran sends through the chokepoint.

The combined effect of the attacks on the oil tankers and the pipeline infrastructure has been to send the message that Saudi oil supplies transported from both the Persian Gulf and Red Sea are vulnerable.

Speaking of the tanker attacks, Gerry Northwood, chairman of risk management and security firm MAST, told Reuters: “This is a pin-prick event, a little needle-like jab at the maritime trade going into the Strait of Hormuz.”

The news agency also quoted Norman Roule, a retired senior US intelligence officer, who said: “There are hundreds, if not a few thousand, small boats moving in that area every day. Many of these vessels are smugglers operating between Iran and the Gulf states. This will make it difficult, but not impossible, to trace any small vessels which may have been involved in the operation.”