UNITED NATIONS U.N. Secretary-General Ban Ki-moon condemned as "deplorable" North Korea's nuclear test on Tuesday, and U.N. diplomats said the Security Council scheduled an emergency meeting to discuss the possibility of imposing new sanctions on Pyongyang.
"The Secretary-General condemns the underground nuclear weapon test conducted by (North Korea) today," Ban's spokesman Martin Nesirky said in a statement. "It is a clear and grave violation of the relevant Security Council resolutions."
"It is deplorable that Pyongyang defied the strong and unequivocal call from the international community to refrain from any further provocative measures," he said.
"The Secretary-General is gravely concerned about the negative impact of this deeply destabilizing act on regional stability as well as the global efforts for nuclear non-proliferation," the U.N. statement added.
South Korea's U.N. mission said it called an emergency meeting of the 15-nation Security Council at 9 a.m. EST (1400 GMT) on Tuesday to discuss the nuclear test. It added that South Korean Foreign Minister Kim Sung-hwan would address the media in New York after the meeting.
South Korea is the president of the council this month, which gives it the possibility to convene meetings and ensure North Korea remains a priority issue for the United Nations' most powerful body for the rest of February.
One Western diplomat said he hoped the council would approve an initial statement condemning the nuclear test on Tuesday and begin work on a more comprehensive council reaction.
Diplomats had said previously that the United States, South Korea and European members would want the Security Council to adopt a resolution imposing new sanctions on Pyongyang in the event of a third nuclear test in defiance of earlier council resolutions.
North Korea carried out nuclear tests in 2006 and 2009, which prompted the Security Council to impose sanctions - including a ban on the import of nuclear and missile technology and an arms embargo - on the impoverished authoritarian state.
Getting approval on a council resolution could take weeks. While China had made clear its opposition to a new North Korean nuclear test, council diplomats say Pyongyang's ally Beijing could be expected to put up some resistance to tough new sanctions to avoid angering North Korea.
But eventually, the diplomats said, China would likely approve some form of sanctions against North Korea in the coming weeks.
Last month the Security Council adopted a resolution that tightened existing sanctions against Pyongyang in response to its December rocket launch. That resolution took a month to agree due to China's initial resistance, diplomats said.