The US is blaming Iran for the strikes on Saudi oil refineries, attacks claimed by the Iranian-backed Houthi rebels.

"Iran has now launched an unprecedented attack on the world's energy supply," Secretary of State Mike Pompeo said in a statement.

At least one Republican lawmaker suggested striking Iranian refineries in response, arguing that only "real" consequences will force Iran to change its malign behavior.

Bilateral tensions between the US and Iran have simmered in the wake of a crisis this past summer that nearly led to an armed conflict between the two countries, but it appears that tensions are again on the rise as the US lays the blame for this devastating attack at Iran's feet.

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The Trump administration is blaming Iran for strikes on two Saudi oil refineries, and at least one Republican lawmaker has already called for retaliation.

Saudi Arabia's oil industry suffered a serious blow Saturday morning when two major refineries were set on fire in a strike that crippled the country's oil production, cutting its output in half. Yemen's Houthi rebels, Iranian-backed forces, claimed responsibility for the attack, calling it "one of the largest executed by our forces" in Saudi Arabia.

The Iranian-backed Houthi rebels have been trading blows with the Saudis for several years. The rebels overthrew the Yemeni government in 2014, and since then, a Saudi-led coalition, one supported by the US, has been fighting to restore that governing authority.

Not only Saudi Arabia but also the US, which has lost two drones to the Houthis this year, have faced a more sophisticated threat from the Houthis due to increased cooperation with Iran, The Wall Street Journal reported, citing US officials and analysts.

Saturday's attacks, while not the first attacks on a Saudi oil facility, were particularly devastating, as this attack may result in the loss of as much as 5% of the world's daily crude oil production.

In the aftermath, President Donald Trump called Saudi Arabia's Crown Prince Mohammed bin Salman and assured him that the US is ready to "cooperate with the kingdom in supporting its security and stability." Later in the day, Secretary of State Mike Pompeo blamed Iran for the attacks.

"Iran has now launched an unprecedented attack on the world's energy supply," Pompeo said on Twitter. Calling on all nations to publicly condemn Iran for the attacks, he said that the US will work to make sure "Iran is held accountable for its aggression."

"Tehran is behind nearly 100 attacks on Saudi Arabia," the secretary added.

Lindsey Graham, a Republican senator from South Carolina, accused the Iranians of "wreaking havoc across the Middle East" on Twitter. "Iran," he added, "will not stop their misbehavior until the consequences become more real, like attacking their refineries."

The latest incident comes after a brief lull in US-Iran tensions after a summer during which a string of troubling incidents nearly triggered armed conflict between the two countries.

In the wake of a series of attacks on tankers from various countries in May and June, Pompeo called the attacks "a threat to international peace and security, a blatant assault on the freedom of navigation, and an unacceptable escalation of tension by Iran."

Read more: Iran just shot down one of the US military's most advanced drones — it costs more than an F-35 stealth fighter

In July, Iranian forces shot down an advanced US reconnaissance drone that the US says was operating in international airspace. The US, according to Trump, was "cocked and loaded to retaliate," but he called off the attack at the last minute. The president insists that had he followed through with his initial plans for an armed response, at least 150 Iranians would have died.

The US and Iran have been at odds since the US withdrew from the Iran nuclear deal last year, but spikes in US pressure coupled with acts of apparent Iranian hostility have triggered various crises. Attacks on commercial shipping started one, and there is certainly the possibility that an attack on critical energy infrastructure could trigger another.

While tensions have simmered in recent weeks, it appears they may again be on the rise as the US responds to what it perceives as Iran's latest act of aggression.