The U.S. blamed Iran for the attacks on oil tankers near the Strait of Hormuz, releasing a video Friday supposedly showing Iran’s Revolutionary Guard removing an unexploded limpet mine from one of the vessels.

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

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

At least one other mine attached to the tanker's hull detonated, causing the blast near the strategic Strait of Hormuz, a key route for oil shipments in the region.

But what are the so-called “limpet mines”?

IRANIAN VESSEL REMOVED UNEXPLODED MINE FROM STRICKEN OIL TANKER IN GULF OF OMAN, US OFFICIALS SAY

The mines got the name from the real limpets, small sea snails that easily cling to hard surfaces and rocks.

The weapon was first developed by the British during World War 2 and is often used in covert action in order to damage ships because they are easily attachable.

There are certain variations, with some detonated by a time fuse while other explode only after the vessel to which the mine is attached travels a specific distance.

In most cases, the mines are magnetic and are easily attachable to the hulls of a ship. They normally just disable rather than sink a vessel.

This wouldn’t the first time Iran used the mines to attack oil tankers. In the 1980s, the “Tanker War” erupted in the midst of the eight-year conflict between Iran and Iraq, threatening to disrupt the global oil supply.

Both countries back then attacked each other oil tankers in the Persian Gulf, with Iran using the limpet mines to cause damage. The conflict prompted then-President Ronald Reagan to intervene and provide protection in the Strait of Hormuz for certain tankers to ensure steady supply of oil.

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President Trump said in an interview with “Fox & Friends on Friday morning that the limpet mine had “Iran written all over it.”

“Iran did do it and you know they did it because you saw the boat,” he said, before pointing to video that the Iranians removing the unexploded mine. “They're a nation of terror and they've changed a lot since I've been president, I can tell you,” he added.

“Iran did do it and you know they did it because you saw the boat.” — President Trump

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Secretary of State Mike Pompeo and other U.S. officials suggested the use of mines in the incident implicates Iran because the limpet mines were used in the May attack on four oil tankers near Emirati port of Fujairah.

“This assessment is based on intelligence, the weapons used, the level of expertise needed to execute the operation, recent similar Iranian attacks on shipping, and the fact that no proxy group operating in the area has the resources and proficiency to act with such a high degree of sophistication,” Pompeo said during a press conference on Thursday.

He added that Iran was working to disrupt the flow of oil through the Strait of Hormuz and this is a deliberate part of a campaign to escalate tension, adding that the U.S. would defend its forces and interests in the region, although he did not elaborate.

Iran's foreign minister, Javad Zarif, denied the accusations and said of the latest incident: "Suspicious doesn't begin to describe what likely transpired this morning."

Iranian President Hassan Rouhani, meanwhile, slammed the U.S. for pursuing an aggressive policy against Iran.

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While the Iranian leader didn’t mention the tankers, he said the U.S. is "using all opportunities for radicalizing the situation, which undermines the stability not only in our region but in the whole world."

He added that America has been "carrying out an aggressive policy and posing a serious threat to regional stability.

Fox News' Lucas Tomlinson and the Associated Press contributed to this report.