The predawn attacks, which sparked large blazes at the Abqaiq and Khurais oil-processing facilities, were claimed by Iranian-backed Huthi rebels in Yemen.
Ten drone attacks for which the United States blames Iran disabled nearly half of Saudi Arabia's oil-production capacity on September 14.

U.S. Secretary of State Mike Pompeo said Tehran had "launched an unprecedented attack" on global energy supplies.

A leading Republican lawmaker, Senator Lindsey Graham of South Carolina, said it was "time" to consider an attack on "Iranian oil refineries if they continue their provocations or increase nuclear enrichment," he said on social media.

Comment: Basically Graham wants any excuse to attack Iran.

Iranian Foreign Ministry spokesman Abbas Musavi was quoted in a statement as denying Iranian involvement and saying "such fruitless and blind accusations are incomprehensible and meaningless."

He added that the accusations were intended to justify "future actions" against Iran.

Iran-backed Huthi rebels in Yemen on September 14 took responsibility for the attack on two oil-processing sites in eastern Saudi Arabia, which reduced production by 5 million barrels a day -- nearly half the kingdom's output -- affecting 5 percent of the world's daily oil production, Reuters and The Wall Street Journal reported.

"There is no evidence the attacks came from Yemen," Pompeo said in a Twitter post in which he also accused Iranian President Hassan Rohani and Foreign Minister Mohammad Javad Zarif of engaging in false diplomacy.

Comment: Houthi's claimed responsibility for the attack, that's usually enough 'evidence' for the US. After 4 years of relentless war crimes and crimes against humanity, victims of the Saudi-led war in Yemen have good reason to fight back.

"Tehran is behind nearly 100 attacks on Saudi Arabia while Rohani and Zarif pretend to engage in diplomacy," Pompeo said in the Twitter post.

Pompeo said that "amid all the calls for de-escalation" of tensions in the Persian Gulf region, "Iran has now launched an unprecedented attack on the world's energy supply."

Comment: There is no precedent of Iran taking action of this kind, it stands to benefit very little, and it would risk losing the support of its influential partners, Russia and China, as well its neighbour and business partner Qatar. The country using this situation to their advantage, at the moment, is the US.

"We call on all nations to publicly and unequivocally condemn Iran's attacks," he said. "The United States will work with our partners and allies to ensure that energy markets remain well supplied and Iran is held accountable for its aggression."

The predawn attacks sparked large blazes at the Abqaiq and Khurais oil-processing facilities that Saudi Energy Minister Prince Abdulaziz bin Salman said "resulted in a temporary suspension of production."

Meanwhile, the U.S. Energy Department said it is "ready to deploy resources" from its strategic oil reserves "if necessary to offset any disruptions to oil markets."

Official data shows the United States has 630 million barrels of strategic oil reserves.

The Huthi Shi'ite insurgent group holds Yemen's capital, Sanaa, and other territory in the Arab world's poorest country.

The targeted production sites are crucial to global energy supplies. The attacks came as Saudi Arabia's state-owned oil giant, Saudi Aramco, prepares for a much-anticipated initial public offering on the stock market.

That stock market listing forms the cornerstone of a reform program proposed by Saudi Arabia's de facto ruler, Crown Prince Muhammad bin Salman, aimed at weaning the Saudi economy off its reliance on oil.

Saudi Aramco -- the world's most profitable company -- describes its Abqaiq oil-processing facility in Buqyaq as "the largest crude oil stabilization plant in the world."

A Saudi-led coalition has been battling the Huthi rebels, which are part of a regional network of militant groups aligned with Iran, since March 2015.

The September 14 attacks highlight how the increasingly advanced weaponry of the Huthi rebels -- from ballistic missiles to unmanned drones -- poses a serious threat to oil installations in Saudi Arabia, the world's top crude exporter.

Comment: The US backed terrorists in Syria regularly use unmanned drones against Russian and Syrian military.

The drone strikes drew swift condemnation from the United States, the United Nations, and Riyadh's Gulf allies -- the United Arab Emirates, Bahrain, and Kuwait.

U.S. President Donald Trump offered bin Salman "his support for Saudi Arabia's self-defense," the White House said.

That followed an earlier statement from Riyadh saying the crown prince told Trump the kingdom was ""willing and able" to respond to the attacks claimed by the Yemeni rebels.

"The United States government is monitoring the situation and remains committed to ensuring global oil markets are stable and well supplied," the U.S. statement said.