Saudi Arabia said it will unveil evidence on Wednesday (September 18th) linking regional foe Iran to attacks on key oil installations, as US Secretary of State Mike Pompeo heads to the kingdom to discuss possible retaliation.
Riyadh has said that the weapons used in the strikes were Iranian-made, but has so far not directly blamed the Islamic Republic.
However, the Saudi defence ministry said its spokesman would present evidence from the site of the weekend attacks that halved Saudi oil production, sending global energy markets into a tailspin.
He "will announce the final results of the investigation and present material evidence and Iranian weapons proving the Iranian regime's involvement in the terrorist attack", the ministry said.
'Real test' of global will
Crown Prince Mohammed bin Salman on Wednesday said the attack on the heart of the kingdom's oil industry was a "real test" of global will in a phone call with South Korea's President Moon Jae-in who called on the international community to take a "firm stance", state media reported.
Late Tuesday, Energy Minister Prince Abdulaziz bin Salman said international investigators, including from the UN, were joining the probe, having announced that output would return to normal by the end of the month.
The kingdom wants "proof based on professionalism and internationally recognised standards", he said.
The Saudis will present the evidence ahead of Pompeo's arrival.
The US chief diplomat is set to meet with Prince Mohammed to discuss how to respond to the strikes, which the US says originated in Iran.
"As the president said, we do not want war with anybody, but the US is prepared," Vice President Mike Pence said in a Tuesday speech in Washington.
A US official, speaking on condition of anonymity, told AFP that the administration has concluded that the attack involved cruise missiles from Iran and that evidence would be presented at the UN General Assembly next week.
Prefer not to meet
Iran's supreme leader Ali Khamenei has ruled out negotiations with Washington "at any level".
This appeared to nix remaining hopes for a meeting between President Donald Trump and his Iranian counterpart Hassan Rouhani at the UN next week.
Meanwhile, Iranian state media reported the trip was looking increasingly unlikely as the US has yet to issue Rouhani and his delegation visas.
Trump on Wednesday said he too had cooled on what had always seemed to be a diplomatic long-shot.
"I never rule anything out, but I prefer not meeting him," Trump said.
Yemen's Iran-backed Houthis (Ansarallah) claimed responsibility for Saturday's oil installation attacks, which took out 6% of global supplies.
But a senior US administration official cast doubt on that claim, saying that while the Houthis said they used 10 drones, one Saudi oil facility was hit "at least 17 times" and another twice by "precision-guided munitions".
Additionally, neither the type of drone "nor the cruise missiles employed in the attack can reach the facilities from Yemen. It is not possible", the official said.
Iran has stuck with its account that the Houthis are responsible.