Saudi Arabia's Ministry of Defence said the missiles and drones used in the attack came from the north, not Yemen to the south as Iran has contended suggesting that Riyadh was in conformity with the US assessment that the attack was launched from Iranian soil.
Tump posted his announcement of new sanctions on Twitter, hours after Saudi Arabia said the strike was a "test of global will".
"I have just instructed the Secretary of the Treasury to substantially increase sanctions on the country of Iran!" he wrote.
Iran has denied involvement in the September 14 raids, which hit the Abqaiq oil-processing plant and the Khurais oil field in Saudi Arabia's eastern province on Saturday morning. Both are major facilities operated by state-owned oil giant Saudi Aramco, the world's largest oil producer. Abqaiq, the world's largest oil-processing plant, is critical to Riyadh's oil infrastructure.
While Yemen's Houthi rebels have claimed responsibility for the attack, the Trump administration has been insisting that Tehran is behind it.
Saudi Arabia's Ministry of Defence said 18 drones and seven cruise missiles were fired from a direction that ruled out Yemen as a source.
The Saudi defence ministry said the wreckage showed the attacks were launched from the north and were "unquestionably sponsored by Iran".
Saudi defence spokesman Col Turki al-Malki showed off what was claimed to be a delta wing of an Iranian UAV (unmanned aerial vehicle) along with other weapons debris.
"Data recovered from the computers shows it (UAV) is Iranian," he said.
According to him, 18 UAVs were fired at the Abqaiq oil facility. He said seven cruise missiles were launched at both targets, of which four struck the Khurais oilfield while the other three fell short of Abqaiq.
He said the "precision impact of the cruise missiles indicate advanced capability beyond the Iran proxy's capacity".
Meanwhile, Saudi Arabian Oil Co., or Saudi Aramco has said that the suspended production capacity would come online by end of the month.
"Saudi Aramco President & CEO Amin Nasser said Tuesday that the company's production capacity, suspended earlier due to terror attacks on its plants at Abqaiq and Khurais, would be fully restored by the end of September," the world's largest oil producer said in the first detailed statement after the attack.
The strike on the Saudi oil field disrupted more than half of Saudi Arabia's oil capacity or 5.7 million barrels per day (mbpd).
Amid the growing hostilities in the region, US Secretary of State Mike Pompeo is on a visit to Jeddah, Saudi Arabia and Abu Dhabi, United Arab Emirates.
"The Secretary will begin his trip in Jeddah, arriving September 18. He will meet with Saudi Crown Prince Mohammed bin Salman to discuss the recent attack on the Kingdom's oil facilities and coordinate efforts to counter Iranian aggression in the region," the US State Department said in a statement.
The US says Iran exploited a gaping hole in the Saudi air defences and fired a volley of drones and cruise missiles, which flew low and at a relatively slow speed, hitting Saudi's Aramco oil sites from the north not the south.
Saudi Arabia's Crown Prince Mohammed bin Salman said on Wednesday that his country was already beefing up its security measures in the air and the water. The Saudis have also committed to joining a US-backed force to protect vital shipping lanes and oil facilities in and around the Persian Gulf.
( With inputs from IANS )