In remarks carried by Iranian state media, Tehran's envoy to Seoul denied his country had anything to do with the incident.

The South Korean cargo ship was hit by unidentified projectiles on May 4 in the strait, a key waterway virtually closed since the United States and Israel launched a war against Iran on February 28.

US President Donald Trump claimed Iran had "taken some shots" at the Panama-flagged vessel, while Tehran had denied responsibility for the attack.

Following a weeks-long investigation, the South Korean government said technical analysis concluded that the unidentified projectile that struck the vessel was "highly likely" an alternative version of the "Noor series developed in Iran".

Seoul summoned the Iranian envoy to "explain the investigation results, convey a strong protest regarding the attack on our vessel, and demand responsible measures, including steps to prevent a recurrence," first vice foreign minister Park Yoon-joo said during a briefing.

Park said the HMM Namu was attacked by two warheads, adding the first was incinerated while the second detonated.

"The engine resembled an Iranian turbojet engine, and parts were found to bear markings presumed to be from an Iranian manufacturer," he said.

Following his meeting at the foreign ministry in Seoul, Iranian ambassador Saeed Koozechi said his country "rejects all allegations made in this regard and has had absolutely no involvement in this matter", according to the official IRNA news agency.

South Korea's Yonhap news agency said Koozechi had expressed regret over the damage to the ship, which had 24 crew members on board.

That damage was about "five metres (16.5 feet) wide and extended roughly seven metres (23 feet) into the hull" on the port-side stern, according to the South Korean government.

The first strike is believed to have ignited an engine room fire, with the second appearing to have caused the blaze to spread rapidly.

A photo released by the foreign ministry shows the ship's engine room badly burned.

Another photo shows a large breach in the outer hull near the stern, with twisted metal and internal frames visible around the impact area.

South Korea, Asia's fourth-largest economy, relies heavily on Middle Eastern fuel imports, most of which transited through the Strait of Hormuz before it was effectively closed.