Russian President Vladimir Putin has blamed the West for increasing tensions in Eastern Europe and suggested a “military-technical” response if his request for security guarantees is not met — while a media mouthpiece for the Kremlin warned that Russia will hold a gun to “America’s head” if Ukraine is allowed to join NATO. In a speech Tuesday to Russian defense ministry officials, Putin said Moscow needs “long-term, legally binding guarantees” from the West that the US and NATO will not deploy missile systems in Ukraine, rather than “verbal assurances.” Russia has massed as many as 175,000 troops as well as...