On 15 April 1969, a United States Navy Lockheed EC-121M Warning Star of Fleet Air Reconnaissance Squadron One (VQ-1) on a reconnaissance mission was shot down by a North Korean MiG-21 aircraft over the Sea of Japan. The plane crashed 90 nautical miles (167 km) off the North Korean coast and all 31 Americans (30 sailors and 1 Marine) on board were killed, which constitutes the largest single loss of U.S. aircrew during the Cold War era.The plane was an adaptation of a Lockheed Super Constellation and was fitted with a fuselage radar, so the primary tasks were to act as a long range patrol, conduct electronic surveillance, and act as a warning device.The Nixon administration did not retaliate against North Korea apart from staging a naval demonstration in the Sea of Japan a few days later, which was quickly removed. It resumed the reconnaissance flights within a week to demonstrate that it would not be intimidated by the action while at the same time avoiding a confrontation.