The comments came during a one-on-one meeting capping Japanese Prime Minister Shinzo Abe's high-stakes visit in Tehran that sought to ease Iran-U.S. tensions, suggested the efforts had failed.
"The shipping industry views this as an escalation of the situation, and we are just about as close to a conflict without there being an actual armed conflict, so the tensions are very high", said Jakob P. Larsen, head of maritime security for BIMCO, the largest worldwide association representing ship owners.
USA allies in Europe and Asia have repeatedly expressed concern that tension between the United States and Iran could escalate into an armed conflict.
Traders might be interested in the upcoming China data dump and the United States retail sales during the later part of the day to determine near-term trade direction.
Such imagery is often hard to declassify and its release appeared to show U.S. efforts to convince the global community of Iran's culpability in Thursday's attacks on the Kokuka Courageous and the Norwegian-owned Front Altair.
"The U.S. economic war and terrorism against the Iranian people as well as its massive military presence in the region have been and continue to be the main sources of insecurity and instability in the wider Persian Gulf region and the most significant threat to its peace and security", the statement said.
Bloomberg reported that an oil tanker had caught fire after leaving the port of Fujairah in the United Arab Emirates, citing an unnamed official from the port.
It was the first evidence publicly put forward by the U.S. to support its claim - announced earlier on Thursday by Secretary of State Mike Pompeo - that Iran was behind the attacks.
Iran's nuclear deal, reached in 2015 by China, Russia, France, Germany, the United Kingdom and the US, saw Tehran agree to limit its enrichment of uranium in exchange for the lifting of crippling sanctions.
Japan's Kokuka Sangyo said its ship was hit twice over a three-hour period.
Magnetic limpet mines were previously used by Iran to sabotage oil tankers during the so-called "Tanker War" in the late 1980s.
How the USA and Iranian governments react to the event will be key.
In a statement on Thursday evening, the Iranian mission to the United Nations said Tehran "categorically rejects the USA unfounded claim with regard to 13 June oil tanker incidents and condemns it in the strongest possible terms". Iran has denied being involved, but it comes as Iranian-backed rebels in Yemen also have launched missile and drone attacks on Saudi Arabia.
The UAE last week said initial findings of its investigation pointed to the likelihood that a "state actor" was behind the bombings, but did not specifically blame Iran.
Tensions have escalated in the Mideast as Iran appears poised to break the 2015 nuclear deal with world powers, an accord that the Trump administration pulled out of past year. In the deal, Tehran agreed to limit its enrichment of uranium in exchange for the lifting of crippling sanctions. Now, Iran is threatening to resume enriching uranium closer to weapons-grade levels if European nations don't offer it new terms to the deal by July 7.
Ultimate authority in Iran is wielded by Khamenei, a hard-line cleric in power since 1989, although the country is run day-to-day by Rouhani, the pragmatist president who won two landslide elections on promises to open Iran to the world.
Already, Iran says it quadrupled its production of low-enriched uranium.