The head of U.S. naval forces in Europe says NATO should invest more in systems and training to counter Russian threats, including anti-submarine capabilities, cyber effects and electronic warfare. Adm. Mark Ferguson, commander of Naval Forces Europe and Africa, said Russia has recently introduced new nuclear-powered attack and ballistic missile submarines into its fleet. Moscow is also arming subs with advanced cruise missiles, according to Ferguson. NATO is not as ready as it should be to counter Russian threats like...