FACTBOX: Reaction to North Korea's nuclear test

(Reuters) - Following is reaction from world leaders and political analysts to North Korea's nuclear test.

UNITED STATES

President Barack Obama said North Korea's nuclear and missile tests were a "matter of grave concern to all nations" and warranted action by the international community.

"North Korea is directly and recklessly challenging the international community. North Korea's behavior increases tensions and undermines stability in Northeast Asia," Obama said in a statement.

Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, said on CBS's "The Early Show" that the test show North Korea to be "a country that I think continues to destabilize that region" and could in the long term be a significant threat to the United States.

UNITED NATIONS

The U.N. Security Council will meet on Monday to discuss the nuclear test, Russia's U.N. ambassador Vitaly Churkin was quoted as saying by Itar-Tass news agency.

U.N Secretary-General said, if confirmed, the test constituted a clear violation of U.N. Security Council resolution 1718. "I am deeply worried by a report of nuclear test by Democratic Republic of Korea," Ban told Danish TV2.

CHINA

China, the North's neighbor and long-time benefactor, said it was "resolutely opposed" to the test, said the Xinhua news agency, quoting the Foreign Ministry.

China however is unlikely to back strong sanctions, analysts said, and its leaders will probably be more careful to balance their anger against worries Pyongyang could make six-party nuclear disarmament talks unsalvageable.

IRAN

Iran has no missile or nuclear cooperation with North Korea, President Mahmoud Ahmadinejad said. Former U.S. President Bush branded both countries as part of an "axis of evil," but Iran says its nuclear program is for peaceful power generation. The West suspects its work has military aims.

"We don't have any cooperation (with North Korea) in this field. We oppose the production, the amassing and proliferation of weapons of mass destruction," Ahmadinejad told a news conference.

Military experts say Iran's Shahab-3 missile is based on the North Korean Nodong missile. Tehran says Shahab-3 has a range of 2,000 km (1,200 miles), which defense analysts say would put Israel and U.S. bases in the Gulf within range.

RUSSIA

Russia's military said the nuclear test had a force of about 20 kilotons, Itar-Tass quoted a source in Russia's defense ministry as saying. A kiloton is equivalent to 1,000 tons of TNT. Russia was concerned by the reports of the test, Interfax news agency quoted Foreign Minister Sergei Lavrov as saying.

The Kremlin condemned the test, saying it caused "deep regret and the most serious concern."

BRITAIN

British Prime Minister Gordon Brown condemned the nuclear and missile tests as "erroneous, misguided and a danger to the world," saying the international community would only treat the North as a partner if it behaved responsibly.

"This act will undermine prospects for peace on the Korean peninsula and will do nothing for North Korea's security," Brown said in a statement.

EUROPEAN UNION

North Korea's nuclear test threatens regional peace and warrants a firm response, European Union foreign policy chief Javier Solana said in a statement which also criticized the North's test launch of short-range missiles.

"We consider it a provocation and we strongly condemn them."

JAPAN

The test was unacceptable and a violation of U.N. Security Council resolutions, Prime Minister Taro Aso said. He said Japan would seek a new resolution condemning the test at the council meeting called for Monday. Kyodo news agency said Japan was also considering tightening its own sanctions on the communist state.

A spokeswoman at Japan's Defense Ministry said that Japan was preparing to fly aircraft as early as today to collect dust in the air in order to measure radiation levels.

On the question of who knew what when: Mitoji Yabunaka, Japan's vice foreign minister, told reporters Japan did not know in advance about the test.

SOUTH KOREA

South Korean President Lee Myung-bak called an emergency meeting of cabinet ministers.

FRANCE

France condemned the test and said it would consult U.N. Security Council partners "on the consequences to draw from this serious act by North Korea, and in particular on strengthening sanctions," the French Foreign Ministry said in a statement.

AUSTRALIA

Foreign Minister Stephen Smith said the test was provocative. "On the basis that North Korea has conducted a nuclear underground explosion, they deserve and get nothing other than our absolute condemnation, and that condemnation should be echoed around our region and the globe," Smith told parliament.

ANALYSTS

* VICTOR CHA, CENTER FOR STRATEGIC & INTERNATIONAL STUDIES'

KOREA CHAIR, FORMERLY WITH THE U.S. NATIONAL SECURITY COUNCIL

" ... The nuclear test is part of a broader effort to improve both the North's long-range ballistic missile technology and its nuclear weapons capability.

" ... These tests could reflect a leadership transition in the North in which the stroke-afflicted leader Kim Jong-il is gradually being succeeded by a coterie of hard-line loyalists and members of the Kim family.

"Internal political fluidity in totalitarian systems like North Korea usually gets externalized in belligerent, not conciliatory behavior."

* JIM WALSH, AN EXPERT IN INTERNATIONAL SECURITY AT THE

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

"The surprise is the timing, that it happened more quickly, much sooner than people expected.

"People reading about this today are going to be worried that there is going to be a war, that this could lead to a military conflict. The answer to that is no. The primary consequences are going to be political and inside North Korea and in the region.

"One has to wonder if this is part of the internal political transition that may be occurring inside North Korea."

* XU GUANGYU, RESEARCHER, CHINA ARMS CONTROL AND

DISARMAMENT ASSOCIATION

"This came unexpectedly quickly. But North Korea has been seeking ways to pressure the United States and South Korea to open up dialogue with them."

"North Korea's strategic objective hasn't changed. That objective is to win the attention of the Obama administration, to push the North Korea issue up the agenda."

* DONG YONG-SUENG, SENIOR FELLOW, SAMSUNG ECONOMIC RESEARCH

"North Korea had already hinted at the possibility of a nuclear test and this test underscored its strong will to hold a nuclear deterrent."

* SCOTT SNYDER, ASIA FOUNDATION, WASHINGTON

"Given internal events related to North Korea's preparations for succession, the statement very much suggests a desire to "deter" external interference in that process and to consolidate a deterrent capacity. This suggests a heightened feeling of vulnerability in Pyongyang."

* KIM SUNG-HAN, KOREA UNIVERSITY PROFESSOR

"The reported test appears to be aimed at securing ultimate endorsement of its nuclear power status from the United States and bringing Washington to the negotiation table."

(Editing by Dean Yates, Paul Tait and Todd Eastham)