Washington: A US Navy submarine has sunk an Iranian naval vessel in the Indian Ocean during the ongoing conflict with Tehran, marking the first time since World War II that an American submarine has destroyed an enemy warship using a torpedo, senior US military officials said on Wednesday. 

The strike took place during Operation Epic Fury, the ongoing US-led military campaign targeting Iran’s missile and naval capabilities.

Announcing the development at a Pentagon press briefing, Secretary of War Pete Hegseth said the attack demonstrated the reach of American naval power.

“In fact, yesterday in the Indian Ocean, an American submarine sank an Iranian warship that thought it was safe in international waters,” Hegseth said.

He added that the vessel had been destroyed in a torpedo strike.

“Instead, it was sunk by a torpedo, quietly - the first sinking of an enemy ship by a torpedo since World War II.”

Chairman of the Joint Chiefs of Staff, Air Force General Dan Caine, confirmed the strike and described it as a rare and significant naval engagement.

“For the first time since 1945, a United States Navy fast-attack submarine has sunk an enemy combatant ship using a single Mark 48 torpedo to achieve immediate effect, sending the warship to the bottom of the sea,” Caine said.

The Iranian vessel had been operating outside the immediate theatre of fighting when it was targeted, according to the Pentagon.

Caine said the strike demonstrated the ability of US forces to track and destroy enemy ships far from the main battle area.

“To hunt, find and kill an out-of-area deployer is something that only the United States can do at this type of scale,” he said.

The sinking is part of a broader campaign aimed at crippling Iran’s naval power. US officials said more than 20 Iranian naval vessels have already been destroyed since the conflict began.

“Second, we are destroying the Iranian Navy, degrading its capacity, capability and ability to conduct operations,” Caine said.

Pentagon officials said the naval campaign is designed to prevent Iran from threatening maritime trade routes and projecting military power beyond its borders.

The operation is being carried out alongside allied forces, including Israel, with US aircraft carriers and strike groups operating across the region.

US military leaders said the neutralisation of Iran’s naval capability is one of the central objectives of the operation, along with the destruction of ballistic missile systems and military infrastructure.

The United States launched Operation Epic Fury earlier this week after escalating tensions with Iran over missile attacks and Tehran’s nuclear ambitions.

The conflict has rapidly spread across multiple domains -- air, sea and cyber -- with US and allied forces targeting Iranian missile launchers, naval bases and military command networks.