May 25 (Bloomberg) -- The United Nations Security Council agreed in an emergency session to condemn the nuclear test North Korea said it conducted and the communist nation’s launch of three short-range missiles.

“The members of the Security Council voiced their strong opposition to and condemnation” of the nuclear detonation and missile launch, Ambassador Vitaly Churkin of Russia, which holds the rotating presidency of the panel this month, told reporters after the meeting in New York.

The Security Council also demanded that North Korea fully comply with previous UN resolutions and agreed to work on a new one, Churkin said.

Ambassador Yukio Takasu of Japan, which is drafting the resolution, said it should contain “additional elements” beyond previously adopted sanctions on North Korea. He said the text should be adopted by the Security Council “as early as possible.”

The Security Council last month unanimously adopted a statement that said North Korea’s April 5 ballistic missile test was in “contravention” of a 2006 resolution barring the country from developing missile technology. That resolution, which was only implemented last month, froze the assets of and banned travel by “persons or entities” involved in nuclear and missile programs.

‘Strong Resolution’

U.S. Ambassador Susan Rice called for a “strong resolution with strong measures,” without going into detail. She said work on the text would begin tomorrow. French Deputy Ambassador Jean- Pierre LaCroix said a resolution should include “new sanctions” against North Korea.

U.S. President Barack Obama earlier called the North Korean actions “a grave threat to the peace and security of the world.”

“The United States and the international community must take action in response,” Obama told reporters in the White House Rose Garden today. “North Korea is not only deepening its own isolation, it’s also inviting stronger international pressure. We will work with our friends and allies to stand up to this behavior.”

The tests, which fulfill a threat made last month, complicate Obama’s efforts to persuade the impoverished country to abandon nuclear weapons development in exchange for economic aid. Kim Jong Il’s government expelled nuclear inspectors and pulled out of disarmament talks after the Security Council censured North Korea for its April 5 missile launch.

‘Growing Belligerence’

The tests demonstrate North Korea’s “growing belligerence,” Michael Mullen, chairman of the U.S. Joint Chiefs of Staff, told CBS television today. Continued development of nuclear weapons by North Korea would “pose a significant threat to the United States.”

Secretary of State Hillary Clinton is “engaged in intensive diplomacy” concerning the tests and spoke today with nations engaged in the six-party North Korea disarmament talks, according to a statement from spokesman Ian Kelly.

UN Secretary-General Ban Ki-moon is “deeply concerned that this act will negatively affect regional peace and stability as well as the global nuclear non-proliferation regime,” the UN said in a statement released in New York.

Ban, a former South Korean foreign minister, said the Security Council should send a “a strong and unified message” asking North Korea to comply with UN resolutions and resume disarmament talks.

‘Military’ Logic

“The suddenness of the nuclear test shows North Korea following military, not diplomatic logic,” said Hideshi Takesada, a professor specializing in Korean issues at Japan’s National Institute for Defense Studies. “They’re showing their nuclear strategies are being finalized. They want to be acknowledged as a nuclear power.”

Russia’s Defense Ministry said the underground detonation occurred at 9:54 a.m. in the northern city of Kilchu and had a yield of between 10 and 20 kilotons. If verified, the result would dwarf that of North Korea’s first nuclear blast in October 2006, which had a yield of less than one kiloton, according to the office of the U.S. Director of National Intelligence.

The atomic bomb dropped on Hiroshima, Japan, on Aug. 6, 1945, which killed an estimated 140,000 people, had an estimated yield of 15 kilotons.

“The current nuclear test was safely conducted on a new higher level in terms of its explosive power and technology,” North Korea’s official Korean Central News Agency said in a statement.

Three Missiles

North Korea also fired three short-range missiles, one around noon and two more later in the day, an official with South Korea’s Joint Chiefs of Staff said, speaking on condition of anonymity. The first had a range of about 130 kilometers, Yonhap News said, quoting an unidentified diplomatic source. The second two were fired as a warning to U.S. spy planes monitoring the nuclear test site, the news service said.

South Korea’s Kospi index fell 2.9 points, or 0.2 percent. The won weakened 0.1 percent to 1,248.82 per dollar, after falling as much as 1.7 percent earlier.

South and North Korea remain technically at war because their 1950-53 conflict ended without a peace agreement.

To contact the reporter on this story: Bill Varner at the United Nations at wvarner@bloomberg.net

Last Updated: May 25, 2009 18:10 EDT