Until there is much more clarity on how a pinpoint attack took out half of Saudi Arabia’s oil production, speculation will swirl about the methods its foes used to strike so deep into the kingdom.
With opinion varying on the weapons used on Saturday to damage a major refinery and an oilfield in the eastern heartland, one of the few things on which specialists and officials agree is that Iranian weapons were probably used in the attack, whether they were drones or missiles, launched from Yemen, Iraq or even Iran.
In Tehran, officials denied Washington’s accusations that Iran was responsible.
They warned the White House that, in case of retaliation, US bases and aircraft carriers in the region are within the 2,000-kilometre range of Iranian missiles.
Washington had disputed a Houthi announcement that the group carried out the attack using 10 drones, saying there was no evidence.
US officials say the attack was more likely to have been carried out by Tehran's proxies in Iraq or launched from Iran.
The Arab Coalition said Iranian weapons were used, and not from Houthi-held territory.
It said the location of the launch was unknown and that an investigation was continuing.
The office of Iraqi Prime Minister Adel Abdul Mahdi said yesterday that Mike Pompeo, the US Secretary of State, indicated to him in a call that the attack had not been launched from Iraq.
Washington made no immediate comment.
Fayez Al Doueri, a prominent Jordanian military commentator, said that in the absence of evidence, the Houthi claim could not be discounted.
“At this stage, the issue is not whether it was Hezbollah, militias in Basra or the Iran Revolutionary Guard Corps,” Mr Al Doueri, a retired general, told The National from Amman.
“What is crucial, militarily, is to protect the Saudi airspace.”
Mr Al Doueri said the latest attack was the third major breach in the past few months that had damaged Saudi oil infrastructure on the upstream and downstream sides.
Saudi Arabia has one of the largest military budgets in the world, per capita and in absolute numbers.
Mr Al Doueri said the kingdom had the technical means to secure its strategic sites.
The attack cut off five per cent of the world’s oil supplies and drove the price of the benchmark Brent crude up 20 per cent before it slipped to 10 per cent, to $66.3 a barrel, by afternoon trading in London.
Fabian Hinz, a researcher at the James Martin Centre for Nonproliferation Studies in California, suggested that missiles developed by Tehran especially for use by its proxies with “no exact Iranian equivalent” may have been involved in the attack.
In an article published this week in the Arms Control Wonk blog, Mr Hinz asked: “Is Iran secretly designing, testing and producing missile systems for exclusive use by its proxies?”
If the answer is yes, it will make dealing with the attack more politically and diplomatically complex, with US President Donald Trump saying said he is waiting to hear from Riyadh after clear results from investigations are reached.