President Donald Trump announced on Oct. 29 that the United States will "immediately" resume nuclear weapons tests.

Russia has in recent months attacked Ukraine with a cruise missile whose secret development prompted Donald Trump to abandon a nuclear arms control pact with Moscow in his first term as U.S. president...

U.S. and Russian officials have both described Poseidon as a new category of retaliatory weapon, capable of triggering radioactive ocean swells to render coastal cities uninhabitable.