The United States will expand its nuclear capabilities to counter concern about Russia's growing arsenal of tactical nuclear weapons, a new Pentagon document says.
- The United States wants to boost its nuclear arsenal to counter perceived challenges from Russia
- The focus will be on smaller atomic bombs, with the argument being that larger weapons are too big to ever be used
- Analysts warn the proposals could increase the risk of miscalculation between the US and Russia
Critics say the move could increase the risk of miscalculation between the two countries.
The policy document, known as the Nuclear Posture Review (NPR), said Russia must be persuaded it would face "unacceptably dire costs" if it were to threaten even limited nuclear attack in Europe.
US officials argued that expanding the US's own low-yield nuclear capability would deter Russia from using nuclear weapons.
Low-yield nuclear weapons have a strength of less than 20 kilotons, about the same power as the atomic bomb dropped on Hiroshima.
The argument for these weapons is that larger nuclear bombs are so catastrophic that they would never be used and do not work as an effective deterrent.
China identified as possible nuclear adversary
US Deputy Secretary of Defence Patrick Shanahan said the NPR would work on upgrading the arsenal, while adhering to existing arms control agreements.
"Our nuclear triad has kept us safe for over 70 years," Mr Shanahan said. "We cannot afford to let it become obsolete."
"The NPR also makes recommendations to keep our deterrent effective for our world today."
The Pentagon-led review of the US nuclear arsenal and the policies that govern it was ordered by President Donald Trump a year ago.
The document was leaked to several media organisations last month, before it was approved by Mr Trump.
A report summarising the review's findings called North Korea a "clear and grave threat" to the US and its allies.
It also cast China as a potential nuclear adversary, saying the US arsenal was tailored to "prevent Beijing from mistakenly concluding" that it could gain advantage by using its nuclear weapons in Asia.
The Pentagon's recently updated National Defence Strategy identified "great power competition" with Moscow and Beijing as a key strategic concern for the US.
The US State Department said it had briefed Russian and Chinese officials on the NPR.
Fears of a new 'arms race'
Jon Wolfsthal, a former top arms control to president Barack Obama, said there was a possibility the policy shift could lead to a miscalculation.
"If we put nuclear weapons on cruise missiles and we launch conventional cruise missiles, how does Russia know that they are conventional?" he said.
Kingston Reif, director for disarmament research at the Arms Control Association advocacy group, said the document could bolster a new kind of arms race.
"It's not an arms race in terms of numbers like during the Cold War, but is an arms race that involves more than just the United States and Russia and it involves upgrading and improving the capability of existing nuclear forces," Mr Reif said.
The review called for continuing the B-83 bomb, the largest nuclear weapon in the US stockpile, until a replacement is found, reversing plans to retire it.
In the longer term, it would also develop a nuclear-armed sea-launched cruise missile - re-establishing a weapon that existed during the Cold War but was retired in 2011 by the Obama administration.