Updated at 10:18 p.m. ET
The Pentagon's Central Command says U.S. aircraft saw a Revolutionary Guard patrol boat and other Iranian vessels "in the vicinity" of the motor tanker Altair, one of two oil tankers attacked in the Gulf of Oman Thursday.
Another crew, from the motor tanker Kokuka Courageous, abandoned their ship, according to the statement, after discovering "a probable limpet mine on their hull following an initial explosion." Central Command says the Iranian patrol boat later approached the craft and was recorded removing an unexploded mine.
The U.S. Navy assisted the ships, one of which was set ablaze. Some 44 crew members abandoned ship; they sustained only minor injuries.
Hours after two oil tankers were hit in a suspected attack in international waters of the Gulf of Oman, Secretary of State Mike Pompeo blamed Iran. He did not offer any evidence that Iran was responsible for the attack, pointing instead to intelligence, the weapons used and recent Iranian attacks on other targets.
Central Command spokesman Lt. Col. Earl Brown released a statement Thursday that said, "The U.S. and our partners in the region will take all necessary measures to defend ourselves and our interests. Today's attacks are a clear threat to international freedom of navigation and freedom of commerce."
"We have no interest in engaging in a new conflict in the Middle East," he added. "We will defend our interests, but a war with Iran is not in our strategic interest, nor in the best interest of the international community."
Last month, four commercial ships in the same passageway sustained serious damage in another episode that Pompeo said was carried out by Iran.
Iran's permanent mission to the U.N. called the U.S. accusations "inflammatory." The statement said, "Iran categorically rejects the U.S. unfounded claim."
It said the U.S., which "unlawfully withdrew" from the international nuclear agreement, has no standing to call on Iran to engage in negotiations and diplomacy. The statement said the U.S. is the main source of "insecurity and instability in the wider Persian Gulf region."
No one immediately claimed responsibility for Thursday's attack.
Speaking to reporters at the State Department in Washington, Pompeo said Iran is using "terror, bloodshed and extortion" in an attempt to pressure the U.S. to ease what he described as a "maximum pressure" campaign against Iran.
"Taken as a whole, these unprovoked attacks present a clear threat to international peace and security, a blatant assault on the freedom of navigation, and an unacceptable campaign of escalating tension by Iran," Pompeo said.
Pompeo provided no specifics about any planned response and took no questions from reporters.
The U.S. has reimposed economic sanctions on Iran since the Trump administration withdrew from the Iran nuclear deal a year ago. The U.S. wants a tougher pact than the one agreed to in 2015. American officials are also calling for Iran to behave like a "normal" nation.
Pompeo focused on diplomatic responses to the attacks on Thursday, a sharp contrast coming after weeks of concern over whether the two countries could be headed toward a military confrontation. "Our policy remains an economic and diplomatic effort to bring Iran back to the negotiating table," he said.
Just a month ago, national security adviser John Bolton, who has helped lead the Trump administration's hard-line stance against Iran, said that while the U.S. is not seeking war with Iran, the Trump administration is "fully prepared to respond to any attack, whether by proxy, the Islamic Revolutionary Guard Corps, or regular Iranian forces."
The Trump administration has sent bombers to the Middle East to counter what top administration officials say are Iranian threats.
The U.S. is expected to consider the issue later on Thursday at the United Nations Security Council, Pompeo said, calling on other nations to join the efforts being pursued by the U.S. Those are expected to be closed consultations in New York.
The morning incidents, which involved two shipping companies and which the White House had earlier described as attacks, roiled a region already unsettled by the escalating conflict between Iran and the United States and some of its allies. Frictions have become so intense that other nations have pleaded with all sides to stay calm rather than provoke an all-out war. On Wednesday, Prime Minister Shinzo Abe of Japan, who was visiting Iran and trying to bridge the gap between that country and the United States, warned of the risk of stumbling into military conflict. The Norwegian shipping company Frontline, which owns Front Altair, said its vessel had experienced an explosion, the cause of which was not yet known. All 23 crew members aboard the vessel carrying naphtha were brought to safety by a nearby vessel, the Hyundai Dubai, according to Norway's VG newspaper, quoting a company official. BSM Ship Management, which operates Kokuka Courageous, said in a statement that all 21 crew members on its ship were rescued by the vessel Coastal Ace with only minor injuries to the crew after an "incident on board which resulted in damage to the ship's hull starboard side."
BSM said that the Kokuka Courageous "remains in the area and is not in danger of sinking" and that the cargo is "intact." Kokuka Courageous was loaded with methanol.
Iran's state-run IRNA news agency reported that multiple tankers were seriously damaged. It said that Iranian rescue crews picked up all 44 crew members from both ships and that the Front Altair had sunk, but Reuters reports that a spokesman for Frontline denied the report.
The Bahrain-based U.S. Navy 5th Fleet said in a statement: "We are aware of the reported attack on shipping vessels in the Gulf of Oman. U.S. Naval Forces in the region received two separate distress calls at 6:12 a.m. local [Bahrain] time and a second one at 7:00 a.m. U.S. Navy ships are in the area and are rendering assistance." Meanwhile, the United Kingdom Maritime Trade Operations, which is run by the British navy, put out an alert warning of an unspecified incident in the Gulf of Oman and urging mariners to exercise "extreme caution" in the area.
In its statement, BSM said its tanker "is about 70 nautical miles from Fujairah and about 14 nautical miles from the coast of Iran."
The last reported position for both vessels, as tracked by the website VesselFinder, placed them in proximity to each other and near the Strait of Hormuz, the narrow chokepoint separating the Gulf of Oman from the Persian Gulf that Iran has repeatedly threatened to close off in response to U.S. sanctions over Tehran's nuclear weapons program.
Japan's Trade Ministry says the two oil tankers carried "Japan-related" cargo, according to The Associated Press.
The price of Brent crude spiked by more than 4% following reports of tanker fires, to $61.80 a barrel at 11:51 a.m. in Dubai, according to Bloomberg. Copyright 2019 NPR. To see more, visit https://www.npr.org.