During the Vietnam War (or American War as the Vietnamese called it) Nakhon Phanom saw some of the most serious fighting between North Vietnamese insurgents and the US forces. During the 1960s, 73 of the 131 subdistrict (tambon) were said[by whom?] to be infiltrated by the Vietnamese and Lao communists, and it was known as the "heartland of insurgency".[citation needed] US and Thai forces established a base at Nakhon Phanom where the Thai military hosted the 56th Air Commando Wing which conducted special operations against both the Ho Chi Minh Trail in Laos and carried out counter-insurgency operations against Thai communist forces while conducting search and rescue operations primarily within Laos and North Vietnam.