The blaze broke out in the engine room in the Strait of Hormuz, with 24 crew aboard, including six South Koreans, and no casualties reported.
Seoul said it was checking intelligence that the Panama-flagged cargo ship may have been attacked, while HMM and authorities investigated the cause and damage.
The incident comes amid heightened tensions in the waterway; South Korea said 26 of its flagged vessels were stranded there and pledged coordination to protect ships and crews.
Was the cargo ship blast an accident, or the first casualty of America's risky 'Project Freedom' mission in the Strait of Hormuz?
With 20,000 sailors trapped and oil prices surging, is this ship explosion the tipping point for a global recession?