Operation Strangle was a sustained interdiction attack on North Korea's supplies and communications by the United Nations forces during the Korean War. Beginning in August 1951, the campaign's 87,552 interdiction sorties were credited with destroying 276 locomotives, 3,820 railroad cars, 19,000 rail cuts, and 34,211 other vehicles. The North Koreans countered the campaign by moving anti-aircraft (AA) guns and crews towards the front line and placing them in higher concentrations around important targets, causing heavy casualties in the UN forces. Despite high losses, Operation Strangle destroyed 900 AA gun positions and damaged 443.