China has accused the US of seeking to militarize outer space, after the Pentagon issued a new policy document which deemed space a “priority domain of national military power.”

Speaking to reporters for a briefing on Wednesday, Chinese Foreign Ministry spokeswoman Mao Ning responded to a Pentagon directive issued in late August discussing possible military operations beyond the earth.

“For a long time, the US has openly defined space as a war-fighting domain. It has built the US Space Force and Space Command, developed and deployed space-based offensive weapons, conducted offensive and defensive military exercises and technology tests, and intensified military cooperation with its allies,” Mao said, arguing “this has heightened the risks of military miscalculation and conflict.”

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The spokesperson went on to accuse Washington of “stonewalling” a “space arms control initiative” led by China and Russia, and of “further aggravating the trend of turning outer space into a weapon and a battlefield.”

In addition to recognizing space as “a priority domain of national military power,” the new US directive said the Pentagon should “protect and defend the use of space for US national security purposes,” as well as “deliver advanced space capabilities to deter conflict and, if deterrence fails, to counter and defeat aggression.”

Mao said the approach outlined in the document “poses a grave challenge to the peace and security of outer space,” and “fully exposes the US ambition of increasing military build-up and war preparedness… in outer space.”

“The US should respect the shared concerns of the international community, immediately stop the negative moves that could undermine security of outer space, step up to its due responsibilities and stop hindering negotiations for a legal instrument on arms control in outer space,” she added.