US President Joe Biden has said that the risk of a nuclear conflict is at its highest level since the 1962 Cuban Missile Crisis. He added that the US was trying to figure out Mr Putin's way out of the war.<br />'' <br />'' The US and the EU have previously said Mr Putin's nuclear saber-rattling should be taken seriously.<br />'' <br />'' However, the US National Security Adviser Jake Sullivan earlier said that, despite Moscow's nuclear hints, the US had seen no signs that Russia was imminently preparing to use a nuclear weapon.<br />'' <br />''  In the meanwhile, Ukraine has been retaking some portions of the  territory occupied by Russia,<br />''During a speech last Friday, President Putin threatened to use every means at his disposal to protect Russian territory.