The new policy -- the first update of the Nuclear Posture Review since 2010 -- pushes modernization of U.S. nuclear weapons, infrastructure and delivery systems. It overturns years of Obama-era policy that sought to reduce the size and power of the United States' nuclear arsenal.
It calls for a "lower-yield" options for ballistic and cruise missiles launched at sea.
"Expanding flexible U.S. nuclear options now, to include low-yield options, is important for the preservation of credible deterrence against regional aggression," the report says.
President Donald Trump ordered Secretary of Defense Jim Mattis to conduct the Nuclear Posture Review one year ago.
In an introductory statement, Mattis said, "We must look reality in the eye and see the world as it is, not as we wish it to be ... in no way does this approach lower the nuclear threshold."
In his own statement, Trump said the updated strategy develops capabilities so that use of a nuclear weapon is less likely.
"It enhances deterrence of strategic attacks against our nation, and our allies and partners, that may not come in the form of nuclear weapons," he said. "And, importantly, it reaffirms our commitment to arms control and nuclear non-proliferation, maintains the moratorium on nuclear testing, and commits to improving efforts to prevent, detect and respond to nuclear terrorism."
During his campaign, Trump promised to expand and strengthen the United States' nuclear arsenal. He repeated that promise Tuesday during his State of the Union speech.
"As part of our defense, we must modernize and rebuild our nuclear arsenal, hopefully never having to use it, but making it so strong and powerful that it will deter any acts of aggression," he said. "Perhaps someday in the future there will be a magical moment when the countries of the world will get together to eliminate their nuclear weapons. Unfortunately, we are not there yet."