(WASHINGTON) -- President Obama called North Korea's latest nuclear test "a highly provocative act" that undermines regional stability and threatens international peace.
North Korea announced earlier on Tuesday that it successfully tested a miniaturized nuclear device underground, according to state media.
Official state media said the test was conducted in a safe manner and is aimed at coping with "outrageous" U.S. hostility that "violently" undermines the country's peaceful, sovereign rights to launch satellites. Unlike previous tests, North Korea used a powerful explosive nuclear bomb that is smaller and lighter, state media reported.
"The danger posed by North Korea's threatening activities warrants further swift and credible action by the international community. The United States will also continue to take steps necessary to defend ourselves and our allies," Obama said in a statement Tuesday morning.
"The United States remains vigilant in the face of North Korean provocations and steadfast in our defense commitments to allies in the region," he added.
The U.N. Security Council will hold an emergency meeting on North Korea's nuclear test later Tuesday morning.
China's Ministry of Foreign Affairs released a statement expressing "firm opposition" to the test.
"We strongly urge the DPRK (North Korea) to abide by its denuclearization commitments, and to refrain from further actions that could lead to a deterioration of the situation. Safeguarding Korean Peninsula and East Asian peace and stability serves the shared interests of all parties," the statement read.
China, North Korea's main ally in the region, has warned North Korea it would cut back severely needed food assistance if it carried out a test. Each year, China donates approximately half of the food North Korea lacks to feed its people and half of all the oil the country consumes.
Suspicions were aroused when the U.S. Geological Survey said it had detected a magnitude 4.9 earthquake Tuesday in North Korea.
The Comprehensive Test Ban Treaty Organization told ABC News, "We confirm that a suspicious seismic event has taken place in North Korea."
"The event shows clear explosion-like characteristics and its location is roughly congruent with the 2006 and 2009 DPRK nuclear tests," said Tibor Toth, executive secretary of the organization.
"If confirmed as a nuclear test, this act would constitute a clear threat to international peace and security, and challenges efforts made to strengthen global nuclear disarmament and non-proliferation," Toth said in a statement on the organization's website.
North Korea threatened in January to carry out a "higher-level" test following the successful Dec. 12 launch of a long range rocket. At the time, North Korea's leader Kim Jong-Un said his country's weapons tests were specifically targeting the United States.
The suspicious tremor comes just hours before President Obama is to give the State of the Union address, and it marks the first diplomatic test in the region for new Secretary of State John Kerry.
Also, South Korea's new president, Park Geun-hye, is scheduled to be sworn in on Feb. 25. One of North Korea's biggest holidays, Kim Jong-Il's birthday, falls on Feb. 16.
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