A screenshot from a YTN network news broadcast on YouTube shows an undated photograph of the HMM Namu, a commercial vessel that caught fire in the Strait of Hormuz on April 4, 2026. (YouTube)
The fire aboard a cargo ship operated by South Korea’s HMM Co. in the Strait of Hormuz last week was caused by unknown airborne objects, according to South Korea’s Foreign Ministry.
Authorities have not yet determined the origin of the attack on the Panama-flagged HMM Namu, which caught fire around 3:30 p.m. May 4 while it was anchored off the United Arab Emirates.
Commercial vessels are at risk in the strait, where Iran has threatened any vessel attempting transit the waterway and the United States is blockading Iranian ports.
None of the 24 crew members on the South Korean vessel — six South Koreans and 18 foreign nationals — were injured in the fire, according to a May 5 report by the Yonhap News Agency. HMM did not respond to requests by phone for comment Wednesday.
Seoul immediately launched an investigation into the incident to determine whether the damage was caused by an external attack or internal factors.
Based on evidence collected onsite, surveillance camera footage and testimony from the vessel’s captain, the government found that a pair of unidentified airborne objects had struck the vessel, said Ministry of Foreign Affairs spokesman Park Il, according to a transcript of his briefing on Sunday in Seoul.
The vessel’s side ballast tank was hit twice in separate strikes about one minute apart, Park said.
The strikes damaged a section of the left stern measuring 16.4 feet wide and 23 feet deep, and bent the hull frame inward, causing part of the outer hull plating to buckle outward, he said. No injuries were reported.
The first strike appears to have ignited the fire where the ballast tank’s upper plating was perforated, while the subsequent strike likely intensified and spread the flames, according to the briefing.
The blast patterns and hemispherical shape of the damage -- roughly three to five feet above sea level – suggest the vessel was probably not hit by a mine or torpedo, Park said.
Authorities have yet to determine the exact type or the size of the airborne objects based on surveillance camera footage. Debris collected from the site will be further examined for possible origins, he added.
Seven experts from Seoul under the Ministry of Oceans and Fisheries conducted the investigation on Friday at the Port of Dubai, according to Park’s briefing
HMM did not respond to phone calls on Monday.
The Ministry of National Defense is in communication about the incident with agencies involved with the investigation and will continue necessary support, deputy spokesman Lee Kyung-ho said at a regular briefing Monday.
President Donald Trump on his social media platform Truth Social said May 4 that Iran had “taken some shots” at the Namu and urged South Korea to join the U.S. in its mission to open the strait.
However, the Iranian Embassy in Seoul said it “firmly rejects and categorically denies any allegations” that Iranian armed forces were involved in the incident, according to a statement posted on its website Thursday.
Trump on May 3 announced Project Freedom to assist commercial vessels trapped by Iranian threats, but paused the effort the next day.
On Monday, Trump said on Truth Social that the most recent peace proposal from Iran was “totally unacceptable,” signaling that Washington’s efforts to negotiate an end to the conflict have hit a wall.
