STORY: The Kremlin lashed out at Joe Biden on Thursday, after the U.S. president called Russian's Vladimir Putin a "crazy SOB". It said Biden had debased the United States, and called his remarks part of a failed "Hollywood cowboy" act.Here's Kremlin spokesperson, Dmitry Peskov."The use of such language against the head of another state by the president of the United States is unlikely to infringe on our president, President Putin. But probably it debases those who use such vocabulary. It may seem as an attempt to appear as a cowboy from Hollywood. But frankly speaking I do not think it is possible. "The U.S. president made the initial comments while addressing threats to the world. Among that list was quote "that guy Putin and others," the risk of nuclear conflict, and the existential threat to humanity from climate change.Peskov said Putin had never addressed Biden using "one crude word" and said that "such vocabulary debases America itself."Putin ally and former president Dmitry Medvedev added the existential threat to the world came from "useless old geezers, like Biden himself." Medvedev also said Biden was "senile" and "ready to start a war with Russia."Biden's comments follow two years of war in Ukraine, the death of Russian opposition leader Alexei Navalny, and U.S. assertions that Russia plans to put a nuclear weapon in space.Those topics have led to the biggest crisis in relations between Russia and the West since the Cold War.Some Russian and U.S. diplomats say they can't remember a time when relations between the world's two biggest nuclear powers were worse.Biden also took aim at Putin last week after Navalny's death in a Russian penal colony was announced, saying it was "a consequence of something that Putin and his thugs did." Russian officials say the West rushed to blame Putin without waiting for evidence.