The US Department of Defense has published its 2018 Nuclear Posture Review, a guiding principle for future US policy on its nuclear weapons.

The Pentagon says it wants to modernize its nuclear "triad" capabilities, including on land, air and sea, by revamping its nuclear arsenal and developing new low-yield atomic bombs. The Pentagon says "lower-yield" weapons, with less powerful explosive capacities for ballistic and cruise missiles launched from submarines, would enhance the credibility of the US arsenal. It also claims that China and Russia are both expanding their nuclear forces and are challenging the free and open international order. The review adds that nuclear weapons could be used to respond to "extreme circumstances", including non-nuclear attacks.