Deteriorating relations between Cambodia and Vietnam reached a crescendo of recrimination when, on 31 December 1977, Radio Phnom Penh, citing "ferocious and barbarous aggression launched by the 90,000 Vietnamese aggressor forces against Democratic Kampuchea", denounced the "so-called Socialist Republic of Vietnam" and announced the "temporary severance" of diplomatic relations.
The public unveiling of the KNUFNS dashed any remaining expectations that Cambodian-Vietnamese disagreements could be solved without further armed conflict, because the Hanoi-backed front openly called for the ouster of the "reactionary Pol Pot-Ieng Sary clique."