South Korea’s Oceans Ministry has said that government investigators have 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, Reuters reports.

The ship’s operator, HMM, says investigators dispatched from South Korea boarded the vessel at around 0600 GMT after it had been towed to a port in Dubai.

The spokesperson said it was too early to estimate when the probe would conclude.

HMM earlier confirmed the ship — HMM Namu — completed berthing in Dubai by 2300 GMT on the day before.

The ship suffered an explosion and fire in the engine-room area earlier this week while anchored near the United Arab Emirates, according to the company and Seoul officials.