UNITED NATIONS - The UN Security Council swiftly agreed on Monday afternoon to strongly condemn North Korea for testing a nuclear device and to begin the difficult task of working out a resolution with sanctions against the Pyongyang regime. The 15-nation council held a brief closed-door session after the council's five permanent members - the United States, Russia, China, Britain and France - along with Japan and South Korea held a separate meeting to consider action against North Korean government. Diplomats from the United States, France and Japan said the council was unanimous in condemning North Korea. They said council agreed to begin drafting on Monday a resolution with sanctions. 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 council also called on all other U.N. member states to abide by sanctions imposed on the North, including embargoes on arms and material that could be used in its nuclear and ballistic missile programs and ship searches for banned weapons. In a statement, Secretary-General Ban Ki-moon urged North Korea to refrain from taking further actions that would increase tensions in the region, and and insisted that the country comply with its obligations and resume "without delay" its participation in the Six-Party Talks, involving North Korea , South Korea, Japan, China, Russia and the United States. Ambassador Churkin, the council president, made clear in a statement that the council's condemnation was only an initial response, and that more will follow. He said it was too early to give any specifics. "The members of the Security Council have decided to start work immediately on a Security Council resolution on this matter," he said. U.S. Ambassador Susan Rice said the 15-member council agreed that work on the new resolution will begin Tuesday. "What we heard today was swift, clear, unequivocal condemnation and opposition to what occurred," she said. France's deputy U.N. ambassador Jean-Pierre Lacroix said France wants the new resolution to "include new sanctions ... because this behaviour must have a cost and a price to pay." Takasu, the ambassador Japan, which is a non-permanent council member, said his country was pleased that the rest of the council agreed there should be a new resolution. But he noted that sanctions imposed against three North Korean companies after Pyongyang's missile test in April obviously had no effect. "So therefore I think we really have to think very carefully what will be an effective way to deal with this kind of behavior," he said. "We have to do something more, and the question is what is more." Churkin was asked whether Russia viewed the nuclear test as more serious than the North's launch of a missile in April. "This is a very rare occurrence as you know, and it goes contrary not only to resolutions of the Security Council but also the (Nuclear) Nonproliferation Treaty and the (Nuclear) Test Ban Treaty," he replied. "We are one of the founding fathers Russia is of those documents, so we think they're extremely important in current international relations. So anything which would undermine the regimes of those two treaties is very serious and needs to have a strong response." Before the council meeting, the five permanent veto-wielding members of the council the United States, Russia, China, Britain and France met behind closed doors for over an hour with the ambassadors of Japan and South Korea. North Korea said the underground nuclear test Monday that was much larger than one it conducted in 2006, which led to the first U.N. sanctions resolution. Russia's Defence Ministry confirmed an atomic explosion occurred early Monday in northeastern North Korea and estimated that its strength was similar to bombs that devastated Hiroshima and Nagasaki in World War II. After the council denounced Pyongyang for its April 5 rocket liftoff, which many nations saw as a cover for testing its long-range missile technology, North Korea announced it was quitting disarmament talks and restarting its atomic facilities. Diplomats said Britain, France, and Japan will push for new sanctions. But Russia and China are seen as more reluctant although they did agree to punitive actions after the 2006 test in resolution 1718. Earlier on Monday, China, the North's neighbor and long-time benefactor, said it was "resolutely opposed" to the test. U.S. President Barack Obama strongly condemned Pyongyang's action and called for a strong international response. "North Korea's nuclear and ballistic missile programs pose a grave threat to the peace and security of the world, and I strongly condemn their reckless action," Obama said at the White House. "The United States and the international community must take action in response."