Russia suspended implementation of the INF Treaty on 4 March after the United States announced its own withdrawal process from the Cold War arms-control agreement.
What happened
Washington accused Moscow of deploying a prohibited missile; Russia denied the allegation and raised counterclaims about US systems. The treaty had eliminated an entire class of ground-launched missiles.
Why it mattered
Its collapse weakened the European security architecture and raised concern about a renewed arms competition.
Context and consequences
Both countries formally left the pact in August, increasing pressure on the remaining framework of bilateral nuclear arms control.
