expression, noun which may take the genitive case particle 'no'
among countries; between countries; international
Used as a noun-like expression followed by の to modify another noun, indicating something that exists or happens between multiple nations.
各国間の協力が不可欠だ。
Cooperation among countries is essential.
各国間の貿易摩擦が問題になっている。
Trade friction between countries has become a problem.
Compound of 各国 (kakkoku, 'each country') + 間 (kan, 'between/among').