China firmly opposes the United States expanding its nuclear arsenal and shirking responsibilities for nuclear disarmament under the pretext of the non-existent "China nuclear threat theory", Chinese Defense Ministry said on Thursday.

The ministry spokesman Senior Colonel Wu Qian made the remarks at a news conference in Beijing in response to media reports that US President Biden approved in March a highly classified nuclear strategy that, for the first time, reoriented US' nuclear deterrent strategy toward the so-called "expanding nuclear arsenal of China".

The US side also said that it would dramatically expand its strategic nuclear arsenal starting from February 2026, when the US-Russia New Strategic Arms Reduction Treaty would expire, so as to simultaneously counter challenges posed by nuclear weapon states including Russia, China, Iran and the Democratic People's Republic of Korea.

Wu said that China pursues a nuclear strategy of self-defense and keeps its nuclear force at the minimum level required for national security.

"It is known to all that the US is in possession of the largest nuclear arsenal in the world, and it follows a nuclear policy that allows first use of nuclear weapons," he said.

In recent years, the US has invested heavily to miniaturize nuclear weapons for real combat, exercised double standard on nuclear proliferation, which severely threatens global strategic stability, the spokesman said.

"We urge the US to abandon 'Cold War' mentality, further reduce its nuclear arsenal in a substantive manner, stop proliferating nuclear material and technology, refrain from extending nuclear deterrence or expanding nuclear alliance and take concrete actions to promote global strategic stability," said Wu.