The U.S. military has released a video that it says shows Iran's Revolutionary Guard removing an unexploded limpet mine from one of the oil tankers targeted near the Strait of Hormuz, suggesting the Islamic Republic sought to remove evidence of its involvement from the scene.

The U.S. Navy rushed to assist the stricken vessels in the Gulf of Oman off the coast of Iran, including one that was set ablaze Thursday by an explosion. The ships' operators offered no immediate explanation on who or what caused the damage against the Norwegian-owned MT Front Altair and the Japanese-owned Kokuka Courageous. Each was loaded with petroleum products, and the Front Altair burned for hours, sending up a column of thick, black smoke.

Iran has denied being involved in the attack, calling it an "unfounded claim" in an "Iranophobic campaign" launched by the U.S. However, Iran previously used mines against oil tankers in 1987 and 1988 in the "Tanker War," when the U.S. Navy escorted ships through the region.

The black-and-white footage, as well as still photographs released by the U.S. military's Central Command, appeared to show the limpet mine on the Kokuka Courageous.

An oil tanker is on fire in the Gulf of Oman on Thursday. Two tankers near the strategic Strait of Hormuz were reportedly attacked on Thursday, an assault that left one ablaze and another adrift as sailors were evacuated from both vessels. (ISNA/Associated Press)

A Revolutionary Guard patrol boat pulled alongside the ship and removed the mine, Central Command spokesman Capt. Bill Urban said.

"The U.S. and the international community stand ready to defend our interests, including the freedom of navigation," Urban said. "The United States has no interest in engaging in a new conflict in the Middle East. However, we will defend our interests."

In a statement issued later Thursday, Iran's ambassador to the United Nations called the remarks from the U.S. "another Iranophobic campaign" and rejected the "unfounded claim" that Iran is responsible for the alleged attacks on two oil tankers near the strategic Strait of Hormuz.

"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.

The assault left one of the vessels ablaze and adrift. Sailors were evacuated from both vessels.

The Sentinel-2 satellite, operated by the European Space Agency, captured an image of the smoke plume coming from one of the tankers. (eobservation/Twitter)

Meanwhile, Arab leaders are meeting in the Saudi city of Mecca to discuss drone strikes on oil installations in Saudi Arabia and attacks on four vessels, including two Saudi tankers, off the U.A.E. coast earlier this month.

Tehran has denied involvement.

U.S. envoy to Iran Brian Hook on Thursday warned that the United States will respond with military force if its interests are attacked by Iran.

Oil prices higher

Benchmark Brent crude spiked at one point by as much as four per cent in trading following the reported attack, to over $62 US a barrel, highlighting how crucial the area remains to global energy supplies. A third of all oil traded by sea passes through the strait, which is the narrow mouth of the Persian Gulf.

West Texas Intermediate moved up by about the same amount to just over $53 US a barrel.

Footage from Iranian state TV shows massive damage to the starboard side of one of the oil tankers <a href="https://t.co/rLdwAealQt">pic.twitter.com/rLdwAealQt</a> —@rafsanchez

UN Secretary General Antonio Guterres strongly condemned the suspected attacks and warned the world cannot afford "a major confrontation in the Gulf region."

He told a meeting of the UN Security Council on co-operation between the United Nations and the League of Arab States that he "strongly" condemns "any attack against civilian vessels," and "facts must be established and responsibilities clarified."

The incident in the sea of Oman marks the latest mysterious incident to target the region's oil tankers. The U.S. alleged that Iran used limpet mines to attack four oil tankers off the nearby Emirati port of Fujairah last month. Iran has denied being involved, but it comes as Iranian-backed rebels in Yemen also have launched missile and drone attacks on Saudi Arabia.

Meanwhile, in Iran, Supreme Leader Ayatollah Ali Khamenei warned that while Tehran doesn't seek nuclear weapons, "America could not do anything" to stop Iran if it did.

Two oil tankers near the strategic Strait of Hormuz were reportedly attacked on Thursday.

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, and suggest the efforts had failed.

"Security is of high importance to Iran in the sensitive region of the Persian Gulf, in the Middle East, in Asia and in the whole world," Iranian President Hassan Rouhani said on Thursday, hours after the tankers were evacuated.

"We have always tried to secure peace and stability in the region," Rouhani said in a speech broadcast live on state television.

Tankers carried methanol, naphtha

A European satellite captured an image of the Front Altair, showing a trail of smoke from the stricken tanker, which is owned by the Norwegian firm Frontline and was en route to Taiwan.

Members of the crew of the Front Altair — 11 Russians, one Georgian and 11 Philippine nationals — were not harmed, Frontline said.

Iranian President Hassan Rouhani and Japan's Prime Minister Shinzo Abe meet with the Iran's Supreme Leader Ayatollah Ali Khamenei in Tehran on Thursday. (Official Khamenei Website)

"They were transferred to an Iranian navy vessel and disembarked at a local port. It is understood they are now being transferred to Bandar Abbas," the company said, referring to a city on the southern coast of Iran.

Japan-based Bernhard Schulte Shipmanagement (BSM) said its oil tanker Kokuka Courageous has also been damaged as the result of a "suspected attack," and the crew of 21 has been safely removed, with one suffering minor injuries. They were also transferred to Bandar Abbas.

"The ship is safely afloat. The hull has been breached above the water line on the starboard side," the company said.

It said the Kokuka Courageous was on passage from Al Jabil, Saudi Arabia, to Singapore with a cargo of methanol. The Front Altair was carrying highly flammable naphtha, according to a senior company official for Taiwan's state oil company, CPC Corp.

Abe cautions against 'accidental conflict'

The timing of Thursday's reported attacks was especially sensitive as Abe's high-stakes diplomacy mission was underway in Iran. Japan's trade ministry said the two vessels had "Japan-related cargo."

On Wednesday, after talks with the Iranian president, Abe warned that any "accidental conflict" that could be sparked amid the heightened U.S.-Iran tensions must be avoided.

His message came just hours after Yemen's Iranian-backed Houthi rebels attacked a Saudi airport, striking its arrivals hall before dawn and wounding 26 people Wednesday.

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 last year.