File photo: Smoke is seen following a fire at an Aramco factory in Abqaiq, Saudi Arabia Photograph:( Reuters )
The Saudi-led military coalition battling the group had said preliminary findings indicated the attack was not launched from Yemen.
Saudi Arabia said on Wednesday that strikes on its oil infrastructure came from the "north" and were sponsored by Iran, but added the kingdom was still investigating the exact launch site.
"The attack was launched from the north and unquestionably sponsored by Iran," defence ministry spokesman Turki al-Maliki said. "We are working to know the exact launch point."
Yemen's Iran-aligned Houthi movement had claimed responsibility for the strikes, but the spokesman for the Saudi-led military coalition battling the group had said preliminary findings indicated the attack was not launched from Yemen.
However, Maliki would not be drawn on whether Saudi Arabia believed Iran would ultimately be found to be the culprit, only saying they were confident they would find where the weapons were fired from.
Maliki displayed pieces of what he said were cruise missiles and drones used in the strike, recovered from the site of Saturday's attack in the country's east.
He said a combination of 18 drones and seven cruise missiles fired at the two key oil installations from a direction that ruled out its southern neighbour Yemen as a source.
The Saudi Arabian spokesman reiterated Riyadh's position that the Iran-backed Huthi rebels in neighbouring Yemen, where a Saudi-led coalition is mired in a five-year conflict, were not responsible for the assault despite claiming it.
"Despite Iran's efforts to make it appear so" they did not originate from Yemen, he said, adding the strike was beyond the capabilities of the militia -- who have however mounted dozens of smaller attacks on Saudi territory.
In addition, "the targeting direction indicates it came from the north," he added.