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 behaviour 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