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