The drone attacks hit the world's largest oil processing plant in Saudi Arabia and an oil field run by Saudi Aramco, causing huge fires in a crucial processor for global energy supplies.
The two fires were brought under control Saturday morning, according to a Saudi Interior Ministry spokesman in a statement published by the Saudi state-owned news agency.
No one immediately claimed responsibility for the attack on the Abqaiq oil processing plant in Buqyaq and the second drone attack on Khurais – the second largest oilfield in the country – although Yemen's Houthi rebels had previously launched drone assaults deep in the kingdom.
The online videos apparently filmed in Buqyaq, located about 330 kilometers north-east of the capital Riyadh, included the sound of gunfire in the background and the flames sprouting from Abqaiq's oil treatment plant.
Smoke rose over the skyline and fiery flames could be seen from a distance.
It was unclear whether there had been injuries in the attacks, nor what effect it would have on oil production in the kingdom, yet the attack will probably further increase tensions in the vast Persian Gulf in the midst of a US-Iranian clash on its unveil a nuclear agreement with world powers.
Saudi Aramco, the state-owned oil giant, did not immediately respond to questions, but describes its Abqaiq oil processing plant in Buqyaq as "the world's largest crude oil stabilization plant".
The kingdom hopes soon to offer a fragment of the company in an initial public offering.
The structure transforms up to seven million barrels of acid crude into sweet crude a day, then subsequently transports it to transshipment points on the Persian Gulf and the Red Sea.
The plant has been targeted in the past by militants.
The suicide bombers declared by Al Qaida attempted but failed to attack the oil complex in February 2006.
The suspect falls on the Houthi rebels of Yemen
While no group immediately claimed responsibility for the attacks, the suspicion of Yemen's Houthi rebels immediately fell, a Saudi-led coalition fought for more than four years.
The rebels supported by Iran hold the capital of Yemen, Sanaa and other territories in the poorest country in the Arab world.
War has become one of the worst humanitarian crises in the world.
The violence has driven Yemen to the brink of famine and has killed over 90,000 people since 2015, according to the US Location and Armed Data Project, which tracks the conflict.
Saudi Arabia supports the president of Yemen Abdrabbuh Mansour Hadi – who was forced to flee the capital Sanaa from the Houti – and led a coalition of regional countries against the rebels.
The coalition launches air strikes almost every day, while the Houthis often launch missiles in Saudi Arabia.
From the beginning of the war led by the Saudis, the Houthi rebels used drones in combat.
The first appeared to be a standard hobby-kit drone, but later came almost identical versions of the Iranian models.
Iran denies providing weapons to Houtis.
The Houthi launched drone attacks against the fundamental east-west pipeline of Saudi Arabia in May, while tensions increased between Iran and the United States.
UN investigators said the new Houtis UAV-X drone, discovered in recent months during the Saudi state-led coalition war in Yemen, probably has a range of up to 1,500 kilometers.
This puts a strain on both the borders of Saudi Arabia and the United Arab Emirates.
Al-Masirah's satellite news channel on Houthi did not immediately recognize the attack on Saturday.
conflict and war disorders,