Two South Koreans and 14 other nationals are being held by Houthi rebels in Yemen.
Sources say a Saudi tugboat towing two South Korean drilling rigs was overtaken by armed assailants off the coast of Yemen’s Kamaran Island on Sunday.
A total of 16 people, including the two Koreans, were on board the vessels.
Houthi leaders are said to have informed the South Korean government that they will release the rigs if they are confirmed to be South Korean.
The tugboat was reportedly transporting the rigs from Saudi Arabia to Somalia. Houthi rebels claim the vessel trespassed into the group's territorial waters.
The South Korean anti-piracy Cheonghae unit, which was located in the Gulf of Oman, was dispatched to the region on Monday.