Russian President Vladimir Putin claimed that Western sanctions on his country have failed, in an address to Russian economists and ministers at an economic forum in St Petersburg on Friday, some four months after Moscow started its war on Ukraine. “The economic blitzkrieg had no chance of success from the very beginning,” Putin told the International Economic Forum. “We are strong people and we can cope with any challenge.” Putin called the sanctions imposed by Western countries in response to Russia’s attack on Ukraine “insane” and “thoughtless.” He said the punitive measures were also hitti…