The attack on an Aramco oil facility in Abqaiq, Saudi Arabia (Picture: PA).
Saudi Arabia has claimed Iranian cruise missiles and drones were used to attack the kingdom's oil industry.
In a news conference held by the Saudi Ministry of Defence spokesperson, Lieutenant Colonel Turki al-Malki, journalists were shown the remains of weapons.
Initially, Yemen's Houthi rebels claimed responsibility for the weekend's attacks, but the news conference heard they were "unquestionably sponsored by Iran".
Col al-Malki did not directly accuse Iran of firing the weapons or launching them from inside Iranian territory. Saudi Arabia has sought help from international investigators and the United Nations.
The US alleges Iran launched the attack. Iran denies being involved in the assault and has threatened the US it will retaliate "immediately" if Tehran is targeted over the attack.
Eighteen drones and seven cruise missiles were launched in the assault, Col al-Malki said, with three missiles failing to make their targets.
He added the cruise missiles had a range of 435 miles, meaning they could not have been fired from inside Yemen.
He played surveillance video footage which he said showed a drone coming in from the north. Satellite images released earlier by the US showed damage largely on the north-facing sides of structures at the sites. He said:
"This attack did not originate from Yemen, despite Iran's best effort to make it appear so."
It comes shortly after former Defence Secretary Liam Fox had said military action against Iran cannot be ruled out following the drone attacks on the Saudi Arabian installations.
Downing Street says the Prime Minister and President Trump have spoken about the need for a united diplomatic response to Saturday's attack on oil facilities in Saudi Arabia.
Iran's president and foreign minister also may skip next week's high-level meetings at the United Nations as the US has yet to issue them visas, IRNA reported.
The UN meeting had been considered as an opportunity for direct talks between Iranian President Hassan Rouhani and President Trump amid a summer of heightened tensions and attacks after America's unilateral withdraw from Iran's nuclear deal with world powers a year ago.
However, the attack in Saudi Arabia and hardening comments from Tehran suggest such talks are increasingly unlikely.