Russian President Vladimir Putin and his allies have issued stark warnings that NATO's support for Ukraine's use of long-range missiles against Russia could escalate into a direct conflict, potentially involving nuclear weapons. Andrei Kolesnik and Sergei Karaganov, both influential figures close to Putin, have suggested nuclear tests or limited nuclear strikes to deter further Western aggression. Putin has reiterated that such actions by NATO would fundamentally change the nature of the conflict, effectively putting NATO at war with Russia. Experts warn that a nuclear test, which Russia has not conducted since 1990, would dramatically escalate tensions. The U.S. and U.K. are cautious about providing Ukraine with long-range missiles due to these potential repercussions, despite ongoing discussions between leaders like President Joe Biden and Prime Minister Keir Starmer.