Original sentence: On 20 August 1950, Premier Zhou Enlai informed the United Nations that “Korea is China’s neighbor ... The Chinese people cannot but be concerned about a solution of the Korean question”—thus, via neutral-country diplomats, China warned the US, that in safeguarding Chinese national security, the would intervene against the UN Command in Korea
Edited sentence: On 20 August 1950, Premier Zhou Enlai informed the United Nations that “Korea is China’s neighbor ... The Chinese people cannot but be concerned about a solution of the Korean question”—thus, via neutral-country diplomats, China warned the US, that in safeguarding Chinese national security, they would intervene against the UN Command in Korea