North Korea says it has successfully carried out a hydrogen bomb test, which if confirmed, will be a first for the reclusive regime and a significant advancement for its military ambitions.<br />A hydrogen bomb is more powerful than plutonium weapons, which is what North Korea used in its three previous underground nuclear tests.<br />"If there's no invasion on our sovereignty we will not use nuclear weapon," the North Korean state news agency said.<br />"This H-bomb test brings us to a higher level of nuclear power."<br />A senior U.S. administration told CNN it could take days to obtain the scientific data to determine whether this was a successful test.<br />The South Korean defense ministry said it too could not immediately confirm the test's success, but the country's foreign ministry hastily convened an emergency meeting.<br />The United Nations Security Council also will hold a meeting later Wednesday.
