The South Korean government warned of growing destruction from a red tide off the country's southern and eastern coasts Sunday, noting the damages have already topped 13 billion won.

The government issued a red tide alert last month for waters off the eastern coast for the first time in six years.

A red tide is a natural phenomenon believed to be caused by a combination of high temperatures, salinity and nutrients. Some experts believe that when these conditions meet low winds and certain rain levels, toxic bacteria, called gymnodinium breve algae, multiply rapidly.

Local governments in the southern and eastern regions have so far reported a combined total of some 13.8 billion won ($12.8 million) in damages, the second highest in the country's history, according to the Ministry of Oceans and Fisheries.

The National Fisheries Research and Development Institute said on Sunday that the red tide is expected to further spread in the upcoming weeks. (Yonhap News)