U.S. Secretary of State Mike Pompeo on Wednesday doubled down on accusations Iran is responsible for the weekend bombing on Saudi Arabia’s oil facilities, telling reporters that the strike was “an act of war.”

Pompeo, speaking from Jeddah, Saudi Arabia, added that even if the "fraudulent claims" of responsibility by the Yemen Houthi rebels were true, "it doesn't change the fingerprints of the [Iran Supreme Leader Ayatollah Ali Khamenei] as having put at risk the global energy supply."

His comments come hours after President Trump tweeted that he had ordered Treasury Secretary Steven Mnuchin to “substantially increase sanctions” on Iran, amid escalating tensions between the two countries.

Earlier this week, Trump said it was "looking like" Iran was responsible for the bombing but did not publically accuse Tehran of the attack.

“Well, it’s looking that way,” the president told reporters at the White House on Monday when asked if Iran was responsible. “We’ll let you know definitively.” He added: “That’s being checked out right now.”

Iran, who has repeatedly denied involvement in the bombings, warned Wednesday that it would "immediately" retaliate against the United States if Tehran is targeted over a crippling weekend attack on Saudi oil facilities.

The threat, which was sent via the Swiss Embassy in Tehran, also condemned previous remarks made by Secretary Pompeo and other high-ranking U.S. officials suggesting Iran was behind the move.

POMPEO ACCUSES IRAN OF 'UNPRECEDENTED ATTACK' AFTER DRONES HIT SAUDI OIL FACILITIES

“Iran’s response will be prompt and strong, and it may include broader areas than the source of attacks,” Iran’s Mehr News Agency reported.

Tehran’s Fars News Agency added that any response would be “rapid and crushing.”

Meanwhile, Saudi officials alleged on Wednesday that Iranian cruise missiles and drones were behind the attack on Sunday, showing journalists remains of the weapons. However, they stopped short of directly accusing Iran of launching the assault.

Saudi military spokesman Col. Turki al-Malki said the attack "came from the north," without saying specifically where it originated. Iraq and Iran are to the north of Saudi Arabia across the Persian Gulf.

"The attack could not have originated from Yemen," he said, disputing the claim by Yemen's Iranian-backed Houthi rebels that they launched the weapons.

Saudi officials said the cruise missile, which had what appeared to be a jet engine attached to it, was a land-attack cruise missile that failed to explode.

"Almost certainly it's Iranian-backed," Prince Khalid bin Bandar, Saudi Arabia's ambassador to the United Kingdom, told the BBC. "We are trying not to react too quickly because the last thing we need is more conflict in the region."

Cmdr. Joshua Frey, a spokesman for the U.S. Navy's 5th Fleet, declined to comment on the Saudi announcement, saying it "would be inappropriate to comment on the status of individual nations and the nature of any potential support."

IRAN CRUISE MISSILES AND DRONES USED IN SAUDI OIL FACILITIES, US OFFICIALS SAY

Iran’s state-run news agency also reported that the country’s president and the foreign minister may not be able to attend next week’s high-level meetings at the United Nations because the U.S. has yet to issue them valid visas.

As the host of the U.N.'s headquarters, the U.S. is mandated to offer world leaders and diplomats visas to attend meetings there. But as tensions have risen, the U.S. has put increasing restrictions on Iranians like Iranian Foreign Minister Mohammad Javad Zarif. Since becoming Iran's president in 2013, Hassan Rouhani has spoken each year at the General Assembly.

The U.N. meeting had been viewed as an opportunity for direct talks between Rouhani and Trump amid of a summer of heightened tensions and attacks in the wake of America’s unilateral withdrawal from Iran’s nuclear deal with world powers a year ago.

NEW UN AMBASSADOR KELLY CRAFT VOWS 'STRONG AMERICAN LEADERSHIP' AS SHE TAKES HER POST

However, the likelihood of such talks decreased dramatically following the Saudi oil attack, U.S. accusations that Iran was behind it and hardening comments from Iran. Yemen’s Iranian-backed Houthi rebels have claimed the attack was in response to the Saudi-led war in Yemen, which has sparked the world’s worst humanitarian crisis and killed tens of thousands of people.

Iran sent a note through Swiss diplomats in Tehran on Monday, reiterating that Tehran denies being involved in the Saudi attack, IRNA reported. The Swiss have looked after American interests in Tehran for decades.

Pompeo is traveling to Saudi Arabia for meetings after Saturday's attack, which hit a Saudi oil field and the world's largest crude oil processing plant.

US SHARES INFO WITH SAUDI ARABIA THAT BLAMES IRAN FOR OIL FIELD ATTACK: REPORT

The coalition aims to secure the broader Persian Gulf region. It includes surveillance of the Strait of Hormuz, the narrow mouth of the Persian Gulf through which a fifth of the world's oil travels, and the Bab el-Mandeb, another narrow strait that connects the Red Sea and the Gulf of Aden off Yemen and East Africa.

The U.S. blames Iran for the apparent limpet mine explosions on four vessels in May and another two in June sailing in the Gulf of Oman near the Strait of Hormuz, something Iran denies being behind. Iran also seized a British-flagged oil tanker and another based in the United Arab Emirates after the British seized a tanker carrying Iranian oil.

ROUHANI SAYS IRAN'S RESPONSE TO BILATERAL TALKS WILL ALWAYS BE 'NEGATIVE'

In Tehran, Rouhani told his Cabinet that Saudi Arabia should see the weekend attack as a warning to end its war in Yemen, where it has fought the Houthi rebels since 2015 and sought to restore the internationally recognized government.

Rouhani said Yemenis "did not hit hospitals, they did not hit schools or the Sanaa bazaar," referring to the Saudi-led coalition's widely criticized airstrikes on civilian targets.

He added that Iran does not want conflict in the region, but it was the Saudi-led coalition that "waged the war in the region and ruined Yemen." Saying the Houthis were responsible for the drone strikes, he said: "They attacked an industrial center to warn you. Learn the lesson from the warning."

Iran's defense minister, Gen. Amir Hatami, also denied his country launched the attack, saying the Houthis had the capability to launch the assault.

Wednesday's announcements come after Saudi Arabia's energy minister said late Tuesday that more than half of the country's daily crude oil production that was knocked out by an attack had been recovered. He said production capacity at the targeted plants would be fully restored by the end of the month, in part by drawing from Saudi reserves of crude oil.

Pompeo was due to land in the Red Sea city of Jiddah, where he was scheduled to meet with Saudi Crown Prince Mohammed bin Salman. Pompeo will later travel to the United Arab Emirates on Thursday to meet with Abu Dhabi's powerful crown prince, Sheikh Mohammed bin Zayed Al Nahyan. Both nations are U.S. allies and have been fighting against the Houthis in Yemen.

Marine Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, said Tuesday that U.S. military experts were in Saudi Arabia working with their counterparts to "do the forensics on the attack" -- gleaning evidence that could help build a convincing case for where the weapons originated.

CLICK HERE FOR THE FOX NEWS APP

On Wednesday, French President Emmanuel Macron's office announced experts from his nation would be traveling to Saudi Arabia to help the kingdom shed light "on the origin and methods" of the attacks. France has been trying to find a diplomatic solution to the tensions between Iran and the U.S., so any conclusion they draw could be used as a third-party assessment of what happened.

The Associated Press contributed to this report.