"All this seriously undermines the strategic mutual trust and increases the nuclear risk. The US owes the international community an explanation," Zhao said.
The spokesman pointed to the fact that the US owns the world's largest and most advanced nuclear stockpile and is expected by the international community to observe all the related responsibilities, such as not to harm the global strategic stability and not to violate the disarmament agreements.
"Not only does the US violate the international consensus and refuse to observe its special responsibility for the nuclear disarmament, but quite the contrary it consciously does the opposite by continuing to maintain the Cold War mentality, instigate interstate competition, unilaterally violate and withdraw from agreements and increase its nuclear stockpile," the spokesman said.
In excerpts, published earlier this week, of US journalist Bob Woodward's upcoming book "Rage" Trump is quoted as telling him that the US has a nuclear weapon unheard of elsewhere in the world, including in China and Russia.
Last year, the US unilaterally withdrew form the 1987 Intermediate-Range Nuclear Forces treaty, which committed it and the other signatory, Russia with the second largest nuclear stockpile, to getting rid of all nuclear and conventional ground-launched ballistic and cruise missiles with ranges of 500 to 5,500 kilometers (310 to 3,417 miles).
The only remaining legally binding US-Russian agreement on nuclear arms control is now the New Strategic Arms Reduction Treaty (New START), in force since 2011 and due to expire in February 2021 with a possibility to be renewed for another five years.
The treaty limits the number of nuclear warheads over permitted 700 delivery systems to 1,500, with each heavy bombers equipped for nuclear armaments counting as one warhead toward this limit, and the number of deployed and non-deployed launchers to 800. It also provides for 18 on-site inspections annually for mutual oversight purposes.
Renewing the New START is a step officials in Russia have repeatedly said they were ready to take, but the US administration maintained that it prefers a new treaty that would include both Russia and China.
Beijing has refused to consider entering any trilateral nuclear arms control pacts with Russia and the US.