(Bloomberg) -- United Nations investigators dispatched to Saudi Arabia after drone and missile attacks on state oil company Aramco in September determined they couldn’t yet verify U.S. and Saudi claims that Iran was behind the strikes.

The UN “is unable to independently corroborate that the cruise missiles and unmanned aerial vehicles used in these attacks are of Iranian origin and were transferred in a manner inconsistent with” UN resolutions, Secretary-General Antonio Guterres wrote in his semi-annual Iran report to the security council obtained by Bloomberg News.

The UN report said investigators were able to examine the debris of the weapon systems used in the attacks on an oil facility in May, on the Abha international airport over the summer and on the Saudi Aramco facilities in September. It added that the UN is “still collecting and analyzing additional information on these cruise missiles and unmanned aerial vehicles” and will report additional findings in “due course.”

But after months of inquiry, the UN has thus far stopped short of backing assertions made by the U.S. and Saudi Arabia. In September, Saudi Arabia’s defense ministry said the attacks were “unquestionably sponsored by Iran,” adding that an assessment of the parts of drones and missiles recovered indicate Iranian origin. The ministry displayed pieces of what it said was the weaponry involved. U.S. Secretary of State Michael Pompeo also blamed Iran, which has repeatedly denied involvement.

In response to invitations from Saudi Arabia, members of the UN traveled to Riyadh in September and November to examine the issue, the report said. U.S. and Saudi reviews of the attack have described it as complex, involving a mix of low-flying drones and cruise missiles coming from the north. The attack exposed glaring vulnerabilities in Saudi Arabia’s defense capabilities despite having spent hundreds of billions of dollars on weaponry in recent years.

Tehran’s Warning

The attacks raised questions about Saudi Arabia’s role as an anchor of stability in global energy markets and was the most daring in a string of tanker bombings and pipeline assaults that began in May, after Tehran warned it was going to respond to U.S. sanctions on its oil exports.

During a visit to Saudi Arabia, UN investigators were provided with the Saudi assessment -- based on photographic comparisons -- that a “misfired land attack cruise missile” bore similarities with the Iranian cruise missile “Ya Ali”. The UN staff was also shown a photograph from an Iranian exhibition in May 2014 of a possible mock-up of a delta wing unmanned aerial vehicle, which Saudi Arabia considered to be similar to the ones used in the Abqaiq attack.

The UN agreed with the Saudi assessment that the number of impact points at the oil facilities in Khurais and Abqaiq was inconsistent with the statements made by Iranian-backed Houthi rebels in Yemen, which claimed responsibility for the attack. Yet it noted the cruise missile used in the attacks bore similar design characteristics to the mock-up of the Quds cruise missile that the Houthis displayed in July 2019.

The UN report also notes that the Houthis have “not shown to be in possession” of the type of drones connected to the attacks. It observed that these unmanned aerial vehicles were equipped with parts similar to an Iranian unmanned aerial vehicle reportedly recovered in Afghanistan in 2016.

To contact the reporter on this story: David Wainer in New York at dwainer3@bloomberg.net

To contact the editors responsible for this story: Bill Faries at wfaries@bloomberg.net, Larry Liebert

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