A JAPANESE-OWNED 21,323-dwt Liberian-flagged chemical tanker, the Chem Pluto, was hit by a drone off India "fired from Iran," according to the US Defence Department, reports Agence France-Presse.

Ambrey, a British maritime security firm, said the "chemical/products tanker was Israeli-affiliated" and was en route from Saudi Arabia to India.

The Wall Street Journal reported that the Dutch company operating the tanker is connected to Israeli shipping tycoon Idan Ofer."

The attack came amid a flurry of drone and missile strikes by Yemen's Iran-backed Houthi forces on a vital Red Sea shipping lane.

Saturday's attack caused no casualties aboard the vessel, the Pentagon statement said, adding that a fire had been extinguished.

The US military "remains in communication with the vessel as it continues toward a destination in India," the statement said.

The drone strike occurred 370 kilometers off the coast of India, it said, adding that no US Navy vessels were in the vicinity.

It was the first time the Pentagon has openly accused Iran of directly targeting ships since the start of Israel's war on the militant group Hamas, which is backed by Iran and is a designated as a terrorist organisation by the US, UK EU and others.

Said British Foreign Secretary David Cameron: "Iran is a thoroughly malign influence in the region and in the world.

"You've got the Houthis, you've got Hezbollah, you've got the Iranian-backed militias in Iraq that have actually been attacking British and American bases. And, of course, Hamas," said the former Prime Minister.

"So you've got all of these proxies, and I think it's incredibly important that, first of all, Iran receives an incredibly clear message that this escalation will not be tolerated," he said.

The Indian navy said it had responded to a request for assistance. There was no immediate claim of responsibility for the strike.