North Korea launched a nuclear test today -- timed perfectly for the United States' reflection of Memorial Day 2009 -- which was severely stronger than the test two years ago, according to reports. Russia said the blast was as strong as Hiroshima in 1945..

Reactions beginning.. a day that was supposed to be quiet for the White House suddenly turns tubulent.. Obama says that the North Korean nuke test is a "grave concern"..

The United Nations is going to meet about the test as South Korea proclaims that the North's test is a threat to peace.. The Yen fell to its lowest level in months after news broke of the nuke test..

The BBC asking a great question about the situation: Should the world engage, appease, oppose?

Russia's military said the latest test had a force of about 20 kilotonnes.. Russia's Defense Ministry confirmed an atomic explosion at 9:54 am (0054 GMT) in northeastern North Korea.

Governments are urging action..

Fresh warnings now that the North could possibly test more.. And notice may not be given.. the first three short-range missiles fired happened less than an hour after the North gave notice of it to the United States..

AP PHOTO