South Korea's Oceans Ministry said on Friday that government investigators had started examining the cause of an explosion and fire aboard a Korean-operated vessel amid uncertainty over whether it had been attacked in the Strait of Hormuz.
The ship's operator HMM said investigators dispatched from South Korea boarded the vessel at around 06:00 GMT after it had been towed to a port in Dubai.
The spokesperson said it was to early to estimate when the probe would conclude.
HMM earlier confirmed the ship, HMM Namu, completed berthing in Dubai by 23:00 GMT on Thursday.
The ship suffered an explosion and fire in the engine room on Monday while anchored near the United Arab Emirates, according to the company and Seoul officials.
All 24 crew members, including six South Koreans, were unharmed.
US President Donald Trump said Iran had fired at the South Korean vessel, and urged South Korea to join US-led efforts to secure shipping through the strait.
South Korea’s presidential office said on Wednesday it had suspended a review of whether to join the US escort operation, dubbed "Project Freedom", after Trump put the plan on hold.
Iran's embassy in South Korea denied responsibility, saying it, "firmly rejects and categorically denies," allegations that Iranian armed forces were involved in damage to the vessel.
Iran’s state-run Press TV later carried commentary suggesting a South Korean vessel had been targeted, but the Iranian embassy said the article was outside commentary and did not represent Tehran’s official position.
South Korea has said it is keeping all possibilities open, including whether the damage was caused by an external attack or an internal malfunction, while prioritising fact-finding before deciding any response.
The Strait of Hormuz normally carries about a fifth of the world's oil and liquefied natural gas, making the incident sensitive for South Korea, which depends heavily on imported energy.
(Reporting by Kyu-seok Shim; Editing by Ed Davies)