Carried out by the Central Intelligence Agency sponsored Groupement Mobile 33, the Desert Rat offensive struck the rear of the 50,000 North Vietnamese troops combating Operation Lam Son 719 beginning on 16 February 1971.

The major threat of Lam Son 719 ended, leaving the communists free to deal with the minor one of Desert Rat.

As a result, during 1969 and 1970, the Central Intelligence Agency (CIA) urged its guerrilla battalions to raid the Trail to disrupt or interdict the supply lines.

Eventually, the South Vietnamese launched Operation Lam Son 719 on 8 February 1971 in a failed incursion to cut the Trail.

When the regimental-size Groupement Mobile 33 (GM 33) mustered there, it was exposed to accounts of PAVN ferocity in the Silver Buckle fighting before being helilifted into action.

As GM 33's troops loaded up at 0730 hours of 16 February 1971 on 14 helicopters of the 21st Special Operations Squadron, they came under communist rocket and mortar fire on the landing zone.

The guerrilla regiment would spend over a month in their position in the rear of the 50,000 communists opposing the South Vietnamese invasion, Lam Son 719.

[4] During the operation, GM 33 troops had recovered a list of 21 communist espionage agents in Moung Phalane from the corpse of a North Vietnamese military intelligence officer.

[7] In the wake of Lam Son 719, Silver Buckle, and Desert Rat, the PAVN extended its territory westward into Laos toward the Kingdom of Thailand to better defend the Trail.