China on Sunday expressed firm opposition to and strongly condemned a new round of nuclear tests that Pyongyang conducted, vowing to "unswervingly push forward the denuclearization of the peninsula".

A photo grab from the official website of China's Foreign Ministry on Sunday shows China expresses firm opposition to and strongly condemned a new round of nuclear tests that Pyongyang conducted.

"Today, the Democratic People's Republic of Korea once again conducted a nuclear test despite widespread opposition from international society. The Chinese government expresses firm opposition to and strong condemnation on this," the Foreign Ministry said in a statement issued on its website on Sunday afternoon.

It is the firm stand of China and a common aspiration of the international community to realize denuclearization of the Korean Peninsula, maintain the nuclear non-proliferation regime and maintain peace and stability in Northeast Asia, the statement said.

"We strongly urge the DPRK side to face the international community's resolve on denuclearization of the peninsula, concretely comply with relevant resolutions of the Security Council, stop taking wrong actions that will deteriorate the situation and go against its own interests and come back to the track of resolving the problem through dialogue," the ministry said.

"China, together with the international community, will comprehensively and completely implement relevant resolutions of the Security Council on the DPRK, unswervingly push forward the denuclearization of the peninsula and unswervingly safeguard peace and stability on the peninsula," it added.

Pyongyang said it set off a hydrogen bomb on Sunday in its sixth nuclear test.