Russia (or its predecessor, the Soviet Union) conducted its first successful nuclear test in 1949.
Notes on verification
Well-documented historical event confirmed by multiple independent, reliable sources including archival and encyclopedic references.
Sources
- List of states with nuclear weapons (en.wikipedia.org)
- https://www.icanw.org/soviet_union_tests_its_first_nuclear_bomb (icanw.org)
- https://www.history.com/this-day-in-history/august-29/soviets-explode-atomic-bomb (history.com)