But European nations appealed to all sides to de-escalate, as statements by the owner of one of the targeted ships appeared to challenge the U.S. account that Iranian naval boats had employed limpet mines.
President Trump insisted that the video released by U.S. Central Command that appeared to show unidentified people in a small boat removing something from the side of a tanker — which officials said was an unexploded mine — was proof that Iran had carried out the attacks.
“Well, Iran did do it,” he told Fox News. “And you know they did it because you saw the boat.”
Depicting Iran as a “nation of terror,” the president’s remarks underscored the urgency that has characterized his administration’s approach to a country it has identified as its primary adversary in the Middle East.
U.S. officials say Thursday’s attacks, like a similar incident off the United Arab Emirates in May, was part of an attempt by Iran’s Islamic Revolutionary Guard Corps to hobble energy commerce as the United States moves to shut off Tehran’s ability to sell oil on international markets.
Iran has denied any involvement in the attacks. Iranian Foreign Minister Mohammad Javad Zarif said the United States “immediately jumped to make allegations against Iran — [without] a shred of factual or circumstantial evidence,” accusing the Trump White House of “economic terrorism” and “sabotage diplomacy.”
The escalating rhetoric on both sides has alarmed allied nations and generated concerns among Democratic lawmakers who fear that the administration, led by national security adviser John Bolton, known for his hawkish views on Iran, could allow a conflict to erupt.
Military officials have scrambled to reinforce a presence in the Middle East — which they had reduced in an attempt to refocus on China and Russia — while also voicing concern about the potential for conflict with a well-armed and unpredictable rival.
Secretary of State Mike Pompeo said this week that the impetus behind the attacks on the Japanese ship Kokuka Courageous and the Norwegian Front Altair was the administration’s “maximum pressure campaign” of sanctions, which is intended to get Iran to negotiate over its nuclear program and its support of militia groups in the region.
“This is a way station to a wider conflict breaking out between Iran and the United States,” said Ali Vaez, senior Iran analyst and Iran project director for the International Crisis Group. “If Iran was behind it, it is very clear the maximum pressure policy of the Trump administration is rendering Iran more aggressive, not less.”
A day after the attacks, numerous questions remained about what occurred and how the administration will respond.
Yutaka Katada, president of the Kokuka Sangyo shipping firm that owns one of the targeted tankers, told reporters Friday in Tokyo: “The crew are saying it was hit with a flying object. They say something came flying toward them, then there was an explosion, then there was a hole in the vessel. Then some crew witnessed a second shot.”
Katada added: “To put a bomb on the side is not something we are thinking. If it’s between an explosion and a penetrating bullet, I have a feeling it is a penetrating bullet. If it was an explosion, there would be damage in different places, but this is just an assumption or a guess.”
He said he did not believe that the tanker was struck “because it was Japanese,” as that would have been difficult for an attacker to determine.
The Courageous was targeted as Japanese Prime Minister Shinzo Abe met with Iran’s supreme leader, Ayatollah Ali Khamenei, in Tehran.
“When the shell hit, it was above the water surface by quite a lot,” Katada said. “Because of that, there is no doubt that it wasn’t a torpedo.”
He said the ship’s crew saw an Iranian military ship in the vicinity Thursday night Japan time, the Reuters news agency reported.
The White House said that Trump and Abe spoke Friday about “the circumstances surrounding the attacks,” and that the president thanked the Japanese leader “for his effort to facilitate communication with Iran.”
Following the attacks, the USS Bainbridge, an Arleigh Burke-class guided missile destroyer that was in the area, took on board 21 crew members from the ship. According to U.S. officials, the crew of the Front Altair boarded Iranian naval vessels after initially being rescued by another ship.
Iranian Foreign Ministry spokesman Seyyed Abbas Mousavi said that “responsibility for the security of the Strait of Hormuz lies with the Islamic Republic of Iran.”
“We showed that we were able to rescue the sailors of the ship as soon as possible,” he said, according to Iran’s state-run Islamic Republic News Agency. The accusation against Iran, he said, is “not only not funny . . . but alarming and worrisome.”
As part of the United States’ effort to make its case about the attacks, officials showed reporters photographs of the Kokuka Courageous with what the Navy identified as a suspected magnetic mine attached to its hull.
One official, who briefed reporters on the condition of anonymity because many elements of the investigation remain secret, said the unexploded device was probably applied by hand from an Iranian fast boat. It is thought to be the same kind of weapon used to blow a hole elsewhere in the tanker and to damage the Front Altair, two officials said.
The officials said the type and timing of the attacks bear Iranian hallmarks. But U.S. officials could not yet say with certainty where the mines were manufactured or exactly how they were laid.
“There’s not too many ways in which this can be done,” one official said. “Very few that don’t involve an individual physically placing it on the ship.”
Before the attacks, Iranian forces fired a surface-to-air missile at an American MQ-9 Reaper drone in the area of the attacks, but they missed, a defense official said Friday. Several days earlier, Yemeni Houthi militants shot down another Reaper in the Red Sea, he said. Those allegations were first reported by CNN.
U.S. officials said several nations are discussing how to respond. One option may be to provide military escorts for commercial tankers moving through the Strait of Hormuz, one official said, although no decision has been made.
The attacks underscored the vulnerability of commerce in a strategic waterway through which one-fifth of the world’s oil passes. It connects energy supplies from Arab nations in the gulf, as well as Iran, to consumers around the globe.
Oil prices rose by as much as 4.5 percent on Thursday before easing back. On Friday, the price of the Brent benchmark crude oil used internationally closed at $62.06 a barrel, up 1.2 percent but still below Thursday’s peak. The price of the U.S. benchmark West Texas Intermediate grade of crude oil closed Friday at $52.51 a barrel, up 0.44 percent.
Trump, in another instance of his binary messaging on foreign affairs, appeared in his remarks to Fox to leave the door open to negotiations with Tehran while critizing its leadership.
“They’ve been told in very strong terms . . . we want to get them back to the table if they want to get back,” he said. “I’m in no rush.”
Officials said the Trump administration was attempting to broaden the international consensus on finding Iran responsible for the recent attacks. That is likely to be a challenge given European nations’ ongoing commitment to the 2015 Iran nuclear deal backed by President Barack Obama and their criticism of the Trump administration’s more-hostile policy.
Germany’s government on Friday called for an investigation into the “extraordinarily worrying” incident, but said it had no information on who carried out the attacks, the Associated Press reported.
A French Foreign Ministry spokesman also expressed concern and called for restraint on all sides.
In Beijing, Foreign Ministry spokesman Geng Shuang said China hopes that “all sides can jointly safeguard navigational safety in the relevant waters,” news agencies reported.
“Nobody wants to see war in the gulf,” he said. “That is not in anyone’s interest.”
Cunningham reported from Istanbul. Denyer reported from Tokyo. William Branigin, John Hudson, Steven Mufson, Karoun Demirjian, Anne Gearan and Carol Morello in Washington and Akiko Kashiwagi in Tokyo contributed to this report.