Both in Cambodia and in Laos , the heavily armed and battle-hardened People 's Army of Vietnam were a valuable ally to the Pathet Lao and the Khmer Rouge forces , providing economic and military aid , also with new weapons , technologies and intelligence . Some claimed that just like the US Army 's relationship with the ARVN , Kingdom of Laos and the Khmer Republic , the PAVN was the real power standing behind them and played key roles in bringing both the Khmer Rouge and Pathet Lao to power . When Pol Pot 's Khmer Rouge began the Cambodian genocide , targeting Vietnamese as well , it was instrumental in toppling his regime
Cambodian genocide
Cambodian genocide
People's Army of Vietnam