BEIRUT – Explosions aboard a pair of oil tankers in the Gulf of Oman on Thursday heightened regional tensions with Iran in an already volatile showdown with Washington and sent energy prices soaring in jittery global markets.
U.S. Secretary of State Michael Pompeo quickly blamed Tehran for what he called "a blatant assault" and cited the action as the "terror, bloodshed and extortion" that is part of Iranian strategy.
The apparent attacks, a month after four other tankers were damaged in mine explosions that the Trump administration also blamed on Iran – without providing evidence – sharply raised fears in the strategically important region that Washington might use such incidents to punish the Islamic Republic even without ironclad proof of its involvement.
Pompeo told reporters in Washington that the assessment was based on U.S. intelligence, the type of weapons used, the level of expertise needed and that none of Iran's proxy groups, which operate in countries across the region, had the resources to carry out an apparent attack like Thursday's.
"These attacks are a threat to international peace and security, a blatant assault on the freedom of navigation, and an unacceptable escalation of tension by Iran," Pompeo said.
He did not elaborate, offer details or take questions in his brief appearance before reporters at the State Department.
U.S. military officials said later there was evidence the Iranians carried out the attacks using mines.
To bolster that claim, late Thursday the military released video taken by a Navy surveillance plane that it said showed a crew from an Iranian patrol boat removing an unexploded mine from the hull of the Kokura Courageous 10 hours after the ship was stricken by an explosion.
The grainy black and white video shows a small boat alongside the tanker. Several crew members are seen near the bow as one pulls a small object off the hull.
At 4:10 p.m. a patrol boat from Iran's Islamic Revolutionary Guard Corps approached the Kokura Courageous and "was observed and recorded removing the unexploded limpet mine," said the statement by Capt. Bill Urban, a spokesman for U.S. Central Command.
A limpet mine is a naval weapon that attaches to a ship with magnets.
Urban said the U.S. also observed Iranian small boats swarmed around the other damaged tanker, the Front Altair, demanding that the ship's crew, who had been rescued by another vessel, be turned over to them.
The rescuers, from a ship called the Hyundai Dubai, "complied with the request and transferred the crew" to the Iranians, Urban said.
Hours earlier, dozens of crew members were rescued after explosions on the Japanese-owned Kokura Courageous and the Front Altair, owned by Norway. Iran has denied any connection with the incident.
The suspected attack on a Japanese-owned vessel came less than a day after Japanese Prime Minister Shinzo Abe made a rare conciliatory visit to Tehran seeking dialogue.
The United States and its Persian Gulf allies, led by Saudi Arabia, have mounted a steady campaign of diplomatic isolation and economic punishment of Iran, which they blame for militancy in the Middle East.
Pompeo said he was instructing U.S. envoys to stress the issue in a Security Council meeting, while the United Nations' top diplomat separately urged a return to calm.
"I strongly condemn any attack against civilian vessels. Facts must be established, and responsibilities clarified," said U.N. Secretary-General Antonio Guterres in a Security Council meeting on cooperation with the Arab League.
"If there is something the world cannot afford, it is a major confrontation in the Gulf region," Guterres said.