On Monday, the UN Security Council unanimously adopted new sanctions against North Korea for its sixth and most powerful nuclear test on Sept. 3. China, a veto-wielding council member, backed the resolution and its ambassador to the UN, Liu Jieyi, said his government "firmly opposes and strongly condemns" the test.
According to the source, the Chinese government previously stopped short of using the word "condemn" and only expressed its firm opposition.
"It's quite a big break from past Chinese responses, and meaningful," the source said on the condition of anonymity.
The Security Council restricted North Korea's oil imports for the first time and banned its textile exports, a key source of revenue.
The US had demanded a complete oil embargo and asset freeze on North Korean leader Kim Jong-un, but reportedly faced resistance from China and Russia. (Yonhap)