U.S. , South Korea and Japan warn of `` significant consequences '' after a bomb test . In a round of calls Sunday , Kerry , Japanese Foreign Minister Fumio Kishida and South Korea 's Kim Sung-hwan all agreed the North must understand `` that it will face significant consequences from the international community if it continues its provocative behavior , '' according to a summary of the calls from the U.S. State Department . " The North Korean government has denied the country carried out any nuclear test. South Korea 's president tells his government to be prepared .
U.S. , South Korea and Japan warn of `` significant consequences '' after a bomb test . " The North Korean government has denied the country carried out any nuclear test. South Korea 's president tells his government to be prepared .