US Democratic presidential hopeful Bernie Sanders has slammed Washington’s attempt to blame Iran for purported attacks on oil tanker vessels in the Sea of Oman, warning that the move is aimed at generating a “pretext for war.”

“The Gulf of Oman incident must not be used as a pretext for war with Iran,” said Sanders on Twitter, insisting that any military action on Iran would not only be illegal, but “an unmitigated disaster for the United States, Iran, the region, and the world.”

The development came as officials from multiple countries, the United Nations as well as one of the owners of the ships struck in the recent incidents have discounted or contradicted Washington’s claim accusing Iran of staging the attacks.

While it remained unclear what exactly happened to the ships, US Secretary of State Mike Pompeo insisted on Thursday that Iran had carried out the attacks on the two tanker vessels without offering any evidence. US client states in the Persian Gulf as well as the UK also followed suit the next day.

Moreover, the US military further published a blurry video clip on Friday with Pentagon officials claiming that it proves commandos of the Iran’s Islamic Revolution Guards Corps (IRGC) had planted explosives on one of the ships. The footage, however, proved not very convincing to authorities of other countries and organizations.

Japanese ship owner contradicts US version of attack

Yutaka Katada, the owner of the Japanese tanker attacked near the Strait of Hormuz, however, offered a different account of the attack on Friday, saying that the Filipino crew of the Kokuka Courageous believed that their vessel had been hit by flying objects rather than a mine.

"The crew are saying it was hit with a flying object. They say something came flying towards them, then there was an explosion, then there was a hole in the vessel," he told reporters. "Then some crew witnessed a second shot."

Further contradicting the US version of events, Katada added: "To put a bomb on the side is not something we are thinking. If it's between an explosion and a penetrating bullet, I have a feeling it is a penetrating bullet. If it was an explosion, there would be damage in different places, but this is just an assumption or a guess."

“Not enough” to prove Iran's guilt.

On Thursday, company officials said the vessel had first been hit by what appeared to be an artillery shell toward the stern, causing a fire in the engine room that was extinguished.

Three hours later, the ship was again attacked on the same side in the center of the hull, at which point the captain felt it was no longer safe and ordered the crew to take to the life boats, officials said.

"When the shell hit, it was above the water surface by quite a lot," Katada further underlined on Friday. "Because of that there is no doubt that it wasn't a torpedo."

German Foreign Minister Heiko Maas, who recently visited Tehran to meet with his Iranian counterpart, Javad Zarif, emphasized that the video was “not enough” to prove Iran's guilt.

Tehran, meanwhile, categorically denied any involvement in the suspicious incidents, with Zarif pointing to the odd timing of the alleged attacks and accusing Washington of moving to “Plan B: Sabotage diplomacy” in a bid to “cover up its economic terrorism” against the Islamic Republic.