Employees got fired. Lets talk, live in the cnn newsroom. Good morning, im carol costello. North korea says its carried out its most powerful nuclear test yet. The explosion registering the force of a 5. 3 earthquake. Kim jonguns government now claiming it can make Nuclear Warheads small enough to fit on to missiles. World leaders are strongly condemning the apparent test. With President Obama saying just moments ago there will be serious consequences. He also said, and im just getting his statement right now, that north Koreas Nuclear test is a grave threat. He says to be clear the United States does foot and will never accept north korea as a nuclear state. We have Suzanne Malveaux on this story. Shell join us in a little bit. Lets head to tokyo now for north koreas side. Will ripley has that. Hi, will. Hi, carol. That brandnew statement from President Obama comes after he was very busy during the overnight hours speaking on the phone separately with the japanese Prime Minister shinz