DUBAI, United Arab Emirates (AP) -- U.S. Secretary of State Mike Pompeo said Thursday that America backs Saudi Arabia's "right to defend itself" after a weekend attack targeted the heart of its oil industry, comments coming after he described the assault as an "act of war."
The attacks have reignited fears over a wider conflagration in the region, as tensions remain high over Iran's collapsing nuclear deal with world powers.
Pompeo's comments on Twitter came as he was in Jiddah, Saudi Arabia, after meeting with Crown Prince Mohammed bin Salman, the kingdom's defense minister. The Saudis on Wednesday displayed missile and drone wreckage at a press conference, and cited other evidence they alleged shows the raid was "unquestionably sponsored by Iran."
Iran, which has denied involvement in the attack, warned the U.S. it will retaliate immediately if it is targeted. Iranian Foreign Minister Mohammad Javad Zarif separately accused U.S. allies and officials of trying to "deceive" President Donald Trump into entering a war against Tehran.
Pompeo wrote his tweet early Thursday after his meeting with Prince Mohammed over Saturday's drone and cruise missile attack on a crucial oil processing facility and oil field. Yemen's Iranian-backed Houthi rebels have claimed the attack, but the U.S. alleges Iran carried out the assault.
Pompeo called the attacks "unprecedented."
"The U.S. stands with #SaudiArabia and supports its right to defend itself," Pompeo said. "The Iranian regime's threatening behavior will not be tolerated."
Pompeo did not elaborate. President Donald Trump has been noncommittal on whether he would order U.S. military retaliation. He separately said Wednesday he is moving to increase financial sanctions on Tehran over the attack, without elaborating. Iran already is subject to a crushing American sanctions program targeting its crucial oil industry.
Saudi Arabia's ambassador to Germany, Prince Faisal bin Farhan, told Deutschlandfunk radio on Thursday that the kingdom was still discussing how it should react to the attacks.
"I won't say right now that a military strike is being considered," the prince said. "It depends upon how the world community deals with this topic."
Pompeo left Jiddah on Thursday heading to the United Arab Emirates to meet with Abu Dhabi's powerful crown prince, Sheikh Mohammed bin Zayed Al Nahyan. The UAE is a close ally of Saudi Arabia and joined the kingdom in its war in Yemen against the Houthis.
The UAE announced Thursday it had joined a U.S.-led coalition to protect waterways across the Mideast after an attack on Saudi oil installations.
The state-run WAM news agency quoted Salem al-Zaabi of the Emirati Foreign Ministry as saying the UAE joined the coalition to "ensure global energy security and the continued flow of energy supplies to the global economy."
Saudi Arabia joined the coalition on Wednesday. Australia, Bahrain and the United Kingdom also are taking part.
Pompeo tweeted his appreciation for the UAE and Saudi Arabia joining the coalition.
"Recent events underscore the importance of protecting global commerce and freedom of navigation," he wrote.
The U.S. formed the coalition after attacks on oil tankers that American officials blame on Iran, as well as Iran's seizure of tankers in the region. Iran denies being behind the tanker explosions, though the attacks came after Tehran threatened to stop oil exports from the Persian Gulf.
At the press conference Wednesday, the Saudis displayed broken and burned drones and pieces of a cruise missile that military spokesman Col. Turki Al-Malki identified as Iranian weapons collected after the attack. He also played surveillance video that he said showed a drone coming in from the north. Yemen is to the south of Saudi Arabia.
Eighteen drones and seven cruise missiles were launched in the assault, Al-Malki said, with three missiles failing to make their targets. He said the cruise missiles had a range of 700 kilometers (435 miles), meaning they could not have been fired from inside Yemen. That opinion was shared by weapons experts who spoke to The Associated Press .
"This is the kind of weapon the Iranian regime and the Iranian IRGC are using against the civilian object and facilities infrastructure," Al-Malki said, referring to Iran's Revolutionary Guard.
He added: "This attack did not originate from Yemen, despite Iran's best effort to make it appear so."
Foreign Minister Jean-Yves Le Drian similarly was skeptical of the Houthi claim of responsibility.
"This is not very credible, relatively speaking," he told CNews television on Thursday. "But we sent our experts to have our own vision of things."
Pompeo, who landed in Saudi Arabia shortly after the news conference Wednesday, took a harder line than his hosts, telling reporters: "The Saudis were the nation that was attacked. It was on their soil. It was an act of war against them directly."
Zarif in his own tweet criticized Pompeo for calling the attack an "act of war."
"'Act of war' or AGITATION for WAR? Remnants of #B_Team (+ambitious allies) try to deceive @realdonaldtrump into war," Zarif wrote, with a hashtag he often used to refer to former national security adviser John Bolton and other world leaders.
He added: "For their own sake, they should pray that they won't get what they seek."
Meanwhile, Iran sent a note to the U.S. via Swiss diplomats Monday, reiterating that Tehran denies involvement in the aerial attack, the country's state-run IRNA news agency reported. The Swiss have looked after American interests in Iran for decades.
"If any action takes place against Iran, the action will be faced by Iran's answer immediately," IRNA quoted the note as saying. It added that Iran's response wouldn't be limited to the source of the threat.
IRNA also reported that Iran's delegation to the annual U.N. General Assembly meeting has yet to receive the necessary U.S. visas. Foreign Minister Mohammad Javad Zarif was to travel to New York on Friday, with Iranian President Hassan Rouhani following on Monday.
The U.N. meeting had been considered as an opportunity for direct talks between Rouhani and Trump.
Asked in Los Angeles whether Rouhani will come to New York, Trump said, "I really don't know. If it was up to me, I'd let them come."
As the host of the U.N.'s headquarters, the U.S. is required to offer world leaders and diplomats visas to attend meetings. But as tensions have risen, the U.S. has put increasing restrictions on Iranians like Zarif.