Saudi Arabia's defence ministry has shown off what it says is wreckage of drones and cruise missiles that proves Iranian involvement in weekend attacks on two oil facilities.
It said 18 drones and seven cruise missiles were fired from a direction that ruled out Yemen as a source.
Yemen's Iran-aligned Houthi rebels had said they were behind the attacks.
Iran has denied any involvement and warned it would retaliate against any attack that targeted it.
The US has stood by its accusation that Iran was behind the attacks. Secretary of State Mike Pompeo said after arriving in Saudi Arabia on Wednesday that it was an "act of war".
What's in the Saudi findings?
The evidence was presented at a defence ministry press briefing, where debris from the drone (UAV) and missile attacks was laid out.
Defence ministry spokesman Col Turki al-Malki said the evidence showed the attacks were launched from the north and were “unquestionably sponsored by Iran”.
However, Col Malki said the Saudis were still "working to know exactly the launch point".
Among the debris was what was said to be a delta wing of an Iranian UAV (unmanned aerial vehicle).
Col Malki said: "Data recovered from the computers [on the UAV] shows it's Iranian."
He said that 18 UAVs had been fired at the Abqaiq oil facility and seven cruise missiles had been launched at both targets. Four cruise missiles struck the Khurais oilfield and the other three fell short of Abqaiq.
Col Malki said the missiles that struck had all come from a northerly direction. He showed video of one UAV hitting Abqaiq, along with maps and photographs of the damage.
He said of the Khurais attack that the "precision impact of the cruise missiles indicate advanced capability beyond the Iran proxy's [Houthi rebel force's] capacity".
Col Malki said details of the launch points could not yet be given, but once they had been determined they would be announced.
He said: "Despite Iran's best efforts to make it appear so, their collaboration with their proxy in the region to create this false narrative is clear."
He called the attacks "an assault on the international community… Those responsible should be held accountable for their actions".