SEOUL - South Korean naval forces rescued 21 sailors and their cargo ship hijacked last week in the Arabian Sea by Somali pirates, Seoul's Joint Chiefs of Staff (JCS) said Friday.

South Korean naval special forces rescue crew members on the Samho Jewelry vessel in the Arabian Sea January 21, 2011. [Photo/Agencies]

The unprecedented rescue operation, initiated early Friday morning in the Arabian Sea, left eight Somali pirates dead and five captivated.

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"The operation demonstrated the government's strong resolution that we will never make concessions about illegal activities by pirates," Lee Sung-ho at the JCS told reporters in a briefing. The South Korean captain has sustained a gun wound on his stomach but is not in a critical condition, the official added.

The 11,500-ton Samho Jewelry was sailing from the United Arab Emirates en route to Sri Lanka when hijacked last Saturday. Twenty-one crew members, including eight South Koreans, two Indonesians and 11 others from Myanmar, were aboard the South Korean-owned cargo vessel.

Seoul had dispatched 300 troops and a 4,500-ton destroyer to secure the release of the crew members, and South Korean President ordered Thursday the defense minister to carry out the operation, also supported by US and Omanese forces.

"(South Korea) will never tolerate any act that threatens life and safety of South Korean nationals," President Lee Myung-bak said in a statement. "I thank the allies who had cooperated on the operation."

The operation comes after another separate release of a South Korean freighter, seized in April last year by Somali pirates. The 300,000-ton oil tanker Samho Dream was released seven months later following an alleged ransom pavement of about $9 million.