Operation Rat Killer

Operation Rat Killer was an operation carried out by Republic of Korea forces and United States advisers in from December 1951 into February 1952 during the Korean War. It was aimed at eradicating communist guerrilla forces operating in zones occupied by the United Nations forces. The operation involved two Korean Army divisions, the Capital Division and the 8th Division, several regiments of the Korean National Police, a ROKAF squadron of Mustang fighter-bombers, and about sixty United States experts. The operation was under the command of General Paik Sun Yup. The operation's particular priority area was the mountainous area of Jirisan.

Before the operation, the guerrilla was allegedly responsible for harassing nearly a third of UN forces and conducting regular attacks on roads and railways used by them. After the operation, the guerrilla forces were greatly weakened, although a resurgence remained a threat until the end of the war.

Background

In 1951, a large number of communist guerrilla groups, ranging in size from a few hundred to several thousand, were operating in territory supposedly controlled by UN forces and were attacking roads and railways, sniping at UN forces, and raising funds from local inhabitants. These guerrilla bands were particularly active in the Jirisan mountains, although sniping and guerrilla activity had been reported even in the area of the capital, Seoul. Local anti-communist militias formed themselves to fight back, sometimes engaging in savage reprisals against villages deemed to be supporting the guerrillas.

Outcome

After the operation, communist guerrilla forces were greatly weakened, although thousands of Republic of Korea police were required to remain in the area, supported by up to 11,000 local militia known as the Young Volunteers, in order to prevent the resurgence of the remaining guerrilla forces who may have numbered about 3,000.

According to Republic of Korea records, 5,800 guerrilla fighters were killed and 5,700 were captured. U.S. records claim 9,000 guerrilla fighters were killed, while some sources estimate as many as 10,000.