Register now for FREE unlimited access to Reuters.comMOSCOW, April 21 (Reuters) - President Vladimir Putin warned the West on Wednesday not to cross Russia’s “red lines”, saying Moscow would respond swiftly and harshly to any provocations and those responsible would regret it.At a time of acute crisis in ties with the United States and Europe, with Russian troops massed near Ukraine and opposition leader Alexei Navalny on hunger strike in jail, the Kremlin leader used his state of the nation speech to project a message of Russian strength and defiance in the face of outside threats."We want...…Register now for FREE unlimited access to Reuters.comMOSCOW, April 21 (Reuters) - President Vladimir Putin warned the West on Wednesday not to cross Russia’s “red lines”, saying Moscow would respond swiftly and harshly to any provocations and those responsible would regret it.At a time of acute crisis in ties with the United States and Europe, with Russian troops massed near Ukraine and opposition leader Alexei Navalny on hunger strike in jail, the Kremlin leader used his state of the nation speech to project a message of Russian strength and defiance in the face of outside threats."We want...WW…