South Korea's newly developed submarine-launched ballistic missile / Courtesy of Defense Ministry

South Korea plans to deploy a newly unveiled indigenous submarine-launched ballistic missile (SLBM) at sea around the second half of next year, sources said Monday.

The country revealed the SLBM last week, announcing its successful test-launch from the 3,000-ton ROK Navy submarine Dosan Ahn Chang-ho, and becoming the world's seventh nation to have proven field operation capabilities of the system.

"Several more tests will be conducted to ensure its reliability. After wrapping up development by early next year, we will begin mass production in the first half of 2022. The missiles will likely then be deployed for actual operations starting in the second half," a government source said.

The country's first 3,000-ton submarine, the Dosan Ahn Chang-ho, is equipped with six vertical launch tubes, and was accepted into the Navy last month.