The US Government publicly accused Iran of attacking two tankers in the Gulf of Oman on Thursday, as US President Donald Trump closed the door on talks between Washington and Tehran.
US Secretary of State Mike Pompeo broke with the administration's more cautious approach in the past month and publicly blamed the Iranian government for the attacks on Japanese and Norwegian-operated tankers in the Gulf of Oman.
“It is the assessment of the United States government that Iran is responsible for the attacks that occurred in the Gulf of Oman today,” Mr Pompeo said.
The UAE Minister of State for Foreign Affairs, Dr Anwar Gargash, said the tanker attacks and the Houthi attack on a Saudi airport represented a "major and dangerous escalation" that required the international community to help protect regional stability and security.
“Wisdom and collective responsibility are needed to prevent more escalation,” Dr Gargash said.
Mr Pompeo also revealed that Iran’s supreme leader, Ayatollah Ali Khamenei, had rebuffed Japanese Prime Minister Shinzo Abe's proposal for negotiations. Mr Abe was in Tehran on Thursday.
Mr Pompeo said it was an insult that Iran would attack a Japanese-operated tanker while hosting Mr Abe.
He also accused Iran of instigating or carrying out attacks on a Saudi airport yesterday, on four tankers off Fujairah in the UAE, and in Iraq and Afghanistan over the past month.
Mr Pompeo urged Iran to respond with diplomacy and “not terror”.
Mr Trump tweeted moments after that the opportunity for diplomacy had been temporarily shut after the attack on the two tankers.
He thanked Mr Abe for his efforts but said: “I personally feel that it is too soon to even think about making a deal. They are not ready and neither are we.”
This is a step back from Mr Trump’s overtures for Iran to come to the table in the past month.
A US defence official said the crew of the USS Bainbridge missile destroyer "saw an unexploded limpet mine on the side of one of the ships attacked on Thursday in the Gulf of Oman", CNN reported.
Later on Thursday, Fox News reported that the Pentagon ordered the dispatch of the navy destroyer USS Mason to the Gulf waters, “to help USS Bainbridge with rescue efforts in wake of tanker attacks today.”
Limpet mines were also used in the Fujairah attack where the UAE, Norway and Saudi Arabia, whose tankers were sabotaged, said a “state actor” was the culprit.
The US government is seeking action at the UN in response to the attack, and Mr Pompeo repeated that diplomatic and economic means would be used to pressure Iran.
At least one of the tankers on Thursday was set ablaze in the assault, forcing the crews of both to abandon ship.
The US Navy assisted both tankers after receiving distress calls early on Thursday morning. Its Fifth Fleet, based in Bahrain, said it was responding to reports of an attack.
"We are aware of the reported attack on tankers in the Gulf of Oman," the Fifth Fleet said.
"US naval forces in the region received two separate distress calls at 6.12am local time and a second one at 7am."
The Norwegian Maritime Authority said three explosions were reported on board the Norwegian-owned tanker MT Front Altair after it was "attacked", along with the Kokuka Courageous.
The vessel was "suspected of being hit by a torpedo" at around 0400 GMT, said Taiwanese refiner CPC Corp, which had chartered the vessel. It said the ship was carrying 75,000 tonnes of naphtha for them.
International Tanker Management, which operates the Front Altair, confirmed that at least one explosion caused a fire on board the ship.
The ship burned for hours afterwards. Flames charred half of one of the vessel's sides and sent thick black smoke into the sky.
The ship, which was built in 2016, had set sail from the Emirati port of Ruwais late on Tuesday local time and was set to arrive at the Taiwanese port of Kaohsiung on June 30.
It is believed that the vessel had been loaded with oil in Abu Dhabi before setting off on its journey.
Its crew of 23 is safe after being taken by the nearby Hyundai Dubai cargo ship, it said.
The second vessel was identified by its manager as the Panama-flagged Kokuka Courageous. It set off from the Saudi port of Al Jubail on June 10 and was on course to reach Singapore by June 22.
Its Japanese operator Kokuka Sangyo said that the methanol tanker came under fire.
"It appears other ships also came under fire," company president Yutaka Katada said in Tokyo, confirming an earlier report from its Singapore management company about a "security incident" in the busy shipping waterway.
"Our crew members made evasive manoeuvres but three hours later it was hit again. The crew assessed that it was dangerous to stay on this ship, and they used lifeboats to escape," added Mr Katada.
Meanwhile, Japan's Economy, Trade and Industry Minister Hiroshige Seko said: "A tanker carrying Japan-related goods was attacked. There were no injuries among the crew members. They got off the tanker. There were no Japanese members."
The attack prompted international concern and calls for restraint. The Arab League said the UN Security Council should act over the attacks, warning that “some parties in the region are trying to instigate fires”.
UN Secretary General Antonio Guterres strongly condemned attacks on the two oil tankers, warning that the world cannot afford a major confrontation in the Gulf region.
"I strongly condemn any attack against civilian vessels. Facts must be established and responsibilities clarified," he told a meeting of the UN Security Council on cooperation between the world body and the Arab League.
Britain said on Thursday that it was deeply concerned by the attacks on vessels in the Gulf of Oman. The EU called for "maximum restraint" to avoid an escalation in the region.
German Foreign Minister Heiko Maas said reports of the attacks were very worrying and could cause an escalation of tension in the region.
"An escalation of the situation is dangerous," said Mr Maas, who is just back from a trip to Iran and other countries in the region.
"These are events that could lead to escalation. We need de-escalation and all sides must contribute to that."
Francois Delattre, France's permanent representative to the UN, said: "The world cannot afford a major confrontation in the Gulf region."
But the Iranian Foreign Minister described the attacks as suspicious, as they occurred during the meeting between Mr Abe and Mr Khamenei.
Javad Zarif made the comment in a tweet: "Suspicious doesn't begin to describe what likely transpired this morning."
Security in the Gulf is of high importance to Iran, Mr Rouhani said on Thursday.
“We have always tried to secure peace and stability in the region,” he said in a speech broadcast live on state television.
Iranian state television said 44 sailors from the two tankers were taken to an Iranian port in the southern province of Hormozgan.
Seoul-based Hyundai Merchant Marine, which operates the Hyundai Dubai cargo vessel, said it sent a lifeboat to rescue Front Altair's 23 crew members before later handing over the rescued crew members to an Iranian rescue boat.
Benchmark Brent crude, apparently reacting to the incident, rose in early trading Thursday to over $61, a 2.3 per cent increase.