Secretary of State Mike Pompeo said Sunday that the United States will guarantee the safe transit of oil through the Strait of Hormuz, and continued to blame Iran for attacks on two tankers last week in the Gulf of Oman.

“We’re going to guarantee the freedom of navigation through the straits,” Pompeo said on “Fox News Sunday.” “This is an international challenge. This is important to the entire globe. The United States is going to make sure that we take all actions necessary, diplomatic and otherwise, to achieve that outcome.”

Pompeo defended U.S. intelligence that he said provided “unmistakable” evidence that Iran was responsible for the tanker attacks on Thursday. Germany’s foreign minister has questioned the utility of a video released by the Pentagon purporting to show Iranians in a small boat removing an exploded mine from one of the tankers, saying it is insufficient to blame Iran. And the owner of the Japanese tanker has said the crew believes the vessel was hit by a flying object, not a mine, as the United States has asserted.

Pompeo said “the world will come to see” much of the intelligence and data the United States has collected and not released publicly yet.

“The American people should rest assured, we have high confidence with respect to who conducted these attacks, as well as half dozen other attacks throughout the world over the past 40 days,” he said.

Iran has denied any responsibility for the suspicious explosions on the tankers. Pompeo has said that Iran is conducting a number of attacks on U.S. allies and interests in an attempt to reverse the administration’s strategy of imposing an escalating series of sanctions to drive Iran’s oil exports to zero. That campaign will continue on the diplomatic and economic front, he said Sunday.

“President Trump has done everything he can to avoid war,” he said. “We don’t want war. We’ve done what we can to deter this. The Iranians should understand very clearly that we will continue to take actions to deter Iran from engaging in this kind of behavior.”

Pompeo said he telephoned his counterparts around the world to stress the risk to the world’s oil supplies. But he sidestepped questions about sending more troops, ships, planes and submarines to the region.

“We’ve taken a handful of those actions to increase the opportunity to convince Iran that these actions aren’t in their best interest,” he said. “And it appears to be Iran that wants to oescalate this conflict.”

Saudi Arabia’s crown prince, Mohammed bin Salman, squarely blamed Iran and allied forces for recent attacks on commercial tankers in the waterways of the Persian Gulf and called on the international community to take a “decisive stance” against what he called Iranian expansionism.

Saudi Arabia “does not want a war in the region, but we will not hesitate to deal with any threat to our people, our sovereignty and our vital interests,” the crown prince said in an interview published Sunday by the Saudi-owned Asharq al-Awsat newspaper.

The comments from Saudi Arabia, Iran’s main regional rival, added to tensions in the Persian Gulf that started ramping up after four tankers were damaged in May, and intensified further last week following explosions on two more ships.. The Trump administration has also blamed Iran for the attacks, and weeks of accusations between Washington and Tehran have led to fears the barbs will escalate into armed conflict between the two sides. Iran has denied out carrying out the attacks.

The European Union and China released statements last week urging Iran and the United States to exercise caution, in a show of international concern that bellicose language – or a single incident – could spark a violent confrontation. In another sign of disquiet among U.S. allies, Japanese officials said the government was seeking more conclusive evidence from the Trump adminstration that Iran was indeed responsible for attacks on the two tankers, including a Japanese-owned vessel, in the Gulf of Oman last week, according to a report Sunday from the Kyodo News agency.

The crown prince, Saudi Arabia’s day-to-day ruler, did not offer new evidence of Iran’s culpability in the tanker attacks, according to a transcript of his interview. Saudi Arabia views Iran as its principal adversary in the Middle East, and the Saudis, along with the United Arab Emirates and Israel, have been key supporters of the Trump administration’s “maximum pressure” strategy against the Iranian government.

In the interview, Mohammed noted that the attack on the tankers on Thursday came on the same day that Japanese Prime Minister Shinzo Abe was visiting Tehran in an effort to ease tensions. Iran “did not respect the prime minister as a guest during his visit, and in effect responded to his efforts by attacking the two oil tankers,” the crown prince said.

After Pompeo accused Iran of orchestrating Thursday’s attacks, the Department of Defense later released a video showing what it said was an Iranian patrol boat removing an unexploded limpet mine – a naval mine that attaches to a target by magnet – from the side of the Kokuka Courageous, a Japanese-owned tanker.

But Japanese officials were unconvinced, Kyodo News said.

“The U.S. explanation has not helped us go beyond speculation,” one unnamed senior government official was reported as saying. Japan has sought more concrete evidence through various channels, Kyodo reported.

The Japanese shipping company that owns the vessel cast doubt on the U.S. version of events on Friday, with the president of Kokuka Sangyo saying that the Filipino crew thought the ship had been attacked by “flying objects” rather than a mine.

On Sunday, Kyodo said “a source close to Prime Minister Shinzo Abe” told the news agency that Pompeo’s evidence did not amount to “definite proof” that Iran carried out the attack. “Even if it’s the United States that makes the assertion, we cannot simply say we believe it,” he said.

In blaming Iran for the attack, Pompeo cited “intelligence, the weapons used, the level of expertise needed to execute the operation, recent similar Iranian attacks on shipping, and the fact that no proxy group operating in the area has the resources and proficiency to act with such a high degree of sophistication.”

An official with Japan’s Foreign Ministry cast doubt on Pompeo’s comment that only Iran has the expertise to carry out the attack. “That would apply to the United States and Israel as well,” the official told Kyodo.

The attack was an embarrassment to Abe, who was meeting Iran’s Supreme Leader Ayatollah Ali Khamenei the same day. Afterwards he described his meeting as “a major step forward toward securing peace and stability” in the region, but experts say he appeared to come away empty-handed.

“The attacks have severely affected the prime minister’s reputation as he was trying to be a mediator between the United States and Iran,” the official close to the premier was quoted as saying. “It is a serious concern, and making mistakes when determining facts is impermissible.”

President Donald Trump and Abe spoke by phone Friday about the attacks and his trip, with the U.S. president thanking the Japanese leader “for his effort to facilitate communication with Iran,” the White House said.

After the call, Abe told reporters that Japan urged “all related countries” to avoid an accidental confrontation or doing anything that would raise tensions.

“Japan adamantly condemns the act that threatened a Japanese ship, no matter who attacked.”