In televised remarks, Putin said Moscow had launched long-range missile attacks against Ukraine's energy, military and communications infrastructure on Monday in retaliation for an attack on a vital bridge linking Russia to the annexed Crimean peninsula over the weekend.Register now for FREE unlimited access to Reuters.comUkrainian officials were exultant after the blast but Kyiv has not claimed responsibility.It is simply impossible to leave crimes of this kind unanswered," Putin said, in opening remarks at a meeting of his powerful Security Council.Cities across Ukraine were left without power or water and several people were killed in Russian missile strikes on more than a dozen Ukrainian cities on Monday morning.He repeated, without providing evidence, his assertion that Ukraine and its NATO backers were behind still-unexplained ruptures to the Nord Stream gas pipelines which run from Russia to Germany under the Baltic Sea."