"Our party has always attached and continues to attach primary importance to strengthening the unity and solidarity of the socialist countries, their close interaction and coordination of foreign policy efforts. The necessity of strengthening the unity of the brother parties, countries and peoples is more urgent than ever before, because international imperialism is today waging a frontal attack against world socialism, making every effort to undermine it from within. This is evidenced in particular by intrigues on the part of the imperialists and hegemonists in regard to People's Poland and socialist Cuba, as well as the brother countries of Indochina. They do not hide their plans to weaken Poland, to detach it from the harmonious family of the socialist community, thus undermining its unified might. Everybody knows what serious consequences would result ^rom disruption of the correlation of military-political forces established on the European continent and throughout the world."
January 1, 1970
https://en.wikiquote.org/wiki/Yumjaagiin_Tsedenbal