United Nations Secretary-General Ban Ki-moon speaks at UN headquarters in New York, January 6, 2016. [Photo/Agencies]

UNITED NATIONS -- UN Secretary-General Ban Ki-moon on Wednesday condemned "unequivocally" the "underground nuclear test" announced by the Democratic People's Republic of Korea (DPRK), saying the act "seriously undermines international non-proliferation efforts."

"This test once again violates numerous Security Council resolutions despite the united call by the international community to cease such activities," Ban told reporters here.

"This act is profoundly destabilising for regional security and seriously undermines international non-proliferation efforts," he added.

"I demand the DPRK cease any further nuclear activities and meet its obligations for verifiable denuclearization," he said.

The surprise announcement by the DPRK that the country successfully conducted its first hydrogen bomb test Wednesday morning jolted the international community, as such a move may dampen the denuclearization process on the Korean Peninsula and threaten regional stability.

The H-bomb test is the fourth nuclear test by the country, which has previously conducted three nuclear tests in 2006, 2009 and 2013 respectively.

The UN Security Council is holding closed-door consultations on the DPRK Wednesday following its announcement of the first hydrogen bomb test.