(BSS/AFP) - South Korea said Tuesday it will "review its position" on joining US operations in the Strait of Hormuz after President Donald Trump urged Seoul to take part following an apparent Iranian attack on one of its ships.

An explosion and fire were reported on a South Korean cargo vessel on Monday in the key waterway, which has been effectively blocked since the Mideast war erupted on February 28.

South Korea`s foreign ministry said Tuesday that all 24 crew members aboard the stricken HMM Namu -- including six South Korean nationals -- were unharmed.

Trump said the incident should prompt South Korea to join American efforts to guide stranded ships through the strait, a major artery for the fuel exports that Seoul relies on.

On Tuesday, South Korea`s defence ministry said it would "carefully review our position", but did not commit to any change.

Seoul would consider its stance based on international law, the safety of international maritime routes, its alliance with the United States, and the security situation on the Korean peninsula, the ministry said.

It added that it had been "actively participating in international discussions on cooperation to ensure safe passage through the Strait of Hormuz".

The HMM Namu is a cargo ship of almost 180 metres (590 feet) sailing under the flag of Panama, data from tracking site MarineTraffic shows.

South Korean officials said the fire on the vessel had been "completely extinguished".