Russia possesses the world’s largest nuclear arsenal (5,580 warheads) and has repeatedly threatened escalation over the Ukraine war. -While the probability of use remains low, four main delivery systems are likely candidates for a “limited” tactical nuclear strike.

The presidents also discussed the Middle East conflict and how Moscow could help deal with Iran and its nuclear programme Russian President Vladimir Putin told US President Donald Trump on Wednesday that he would have to respond to Ukrainian drone attacks on Russia's nuclear-capable bomber fleet,

Trump has been hesitant to impose new sanctions on the already heavily sanctioned Russia, saying on Wednesday that additional penalties might interfere with ceasefire negotiations. “If I think I’m close to getting a deal,