Few things worry NATO like Russia's Yasen-class submarines, and Moscow may be planning to build even more of them

• Despite high-profile losses, Russia's navy has been largely untouched by the war in Ukraine.
• Russian submarines, especially Yasen-class cruise-missile subs, are a top concern for NATO.
• Russia may expand the Yasen-class program, with reports indicating three more subs will be built.

Russia's navy has been largely untouched by the war in Ukraine, despite high-profile losses, and Moscow plans to continue investing in it, including by building more of the Yasen-class submarines that have become a top concern for NATO.