China summoned North Korea’s ambassador on Tuesday to deliver a stern protest over its ally’s latest nuclear test in a sign of Beijing’s wavering patience towards the pariah state.

Chinese foreign minister Yang Jiechi expressed Beijing’s “strong dissatisfaction and firm opposition” to the nuclear test and demanded Pyongyang to cease making further threats, the foreign ministry said in a statement posted on its website.

Yang called for the North to “return to the correct channel of dialogue and negotiation” and reiterated “China’s desire for peace and stability on a nuclear-free Korean Peninsula”.

The ministry did not say if North Korean ambassador Ji Jae Ryong made any response.

Pyongyang, however, warned that Tuesday’s test was merely its “first response” to what it says is “US hostility”, and said it would carry out “second and third measures of greater intensity”, reports The Associated Press.

The dressing-down of the North Korean ambassador reflects China’s growing displeasure after earlier agreeing to tighten UN sanctions against North Korea after its rocket launch in December. But it’s tough stance would unlikely go so far as abandoning its communist ally, analysts said.