Davos - Russia is the main threat to the "liberal" world order, US Vice President Joe Biden told the Davos elite on Wednesday, in his final speech before leaving office.Biden used the big stage of the World Economic Forum in the posh Swiss resort to warn of threats posed by the Kremlin two days before Donald Trump's administration takes over in Washington.Though he also mentioned China and threats from the Middle East, his attack on Vladimir Putin's Russia was a direct warning to Trump, who is accused of cosying up to the Russian president."The greatest threat ... springs from the external actors who equate their success on fracturing the liberal international order," Biden said."I'm not going to mince words, this movement is principally led by Russia," added the 74-year-old, who used the Davos forum to promote his signature campaign against cancer. Biden laid down his assessment a day after China's President Xi Jinping gave a landmark speech at Davos that stressed his commitment to globalisation, in contradiction to Trump's protectionist approach.Biden, known for his everyman touch, is increasingly seen as a standard-bearer for the Democrats against Trump, who won the US presidency on a wave of middle-class and white voter discontent. Putin is "working with every tool available to them to whittle away at the edges of the European project," Biden told the Davos audience, who gave him a standing ovation as he came on stage.Putin is "testing the faultlines among Western nations" and working to return the world to a system "defined by spheres of influence".Unshakable commitment"We even saw it in the cyber intrusions against political parties and individuals in the United States," he said, after a US intelligence report that Russia worked to tip the election in Trump's favour."Again, their purpose is clear, to collapse the liberal international order," Biden said.Biden also gave a heated defence of NATO after Trump on Monday slammed the US-led military alliance as "obsolete"."The single greatest bulwark for our transatlantic partnership is the unshakeable commitment of the United States to all our NATO allies," Biden said."An attack on one is an attack on all. That can never be called into question."Biden also had strong words for the world's richest one percent, hugely represented in the Davos audience."The top one percent are not carrying their weight," he said, urging them to invest in education.He also echoed Xi in warning against protectionism but stressed "that globalisation has not been an unalloyed good".Private life"It has deepened the rift between those racing ahead at the top and those struggling to hang on in the middle, or falling to the bottom," he said.Biden assured his audience that he would continue to fight for liberal values."As I re-enter private life, I want to assure you today that I will stand with you as you carry this fight forward," he said.Biden has said he will continue his work to promote cancer research once he leaves office on Friday.The vice president lost his son Beau Biden to brain cancer in 2015. The US administration soon after announced a cancer "moonshot" programme intended to speed up research into the disease.On Monday in Davos, Biden urged the Trump administration to continue the programme.