U.S. prepared to do what's needed to push back at N Korea threat-Kerry

WASHINGTON (Reuters) - The United States is prepared to do what is needed to work with allies to defend against a growing threat from North Korea, U.S. Secretary of State John Kerry said on Friday after Pyongyang conducted its fifth and biggest nuclear test. "We are prepared to take whatever measures are necessary to ensure our alliances continue to defend against this growing threat to international peace and security," Kerry said in a statement. Kerry said the United States remained open to "credible and authentic" talks on the denuclearization of the Korean peninsula, but added that North Korea had shown it would not be a credible negotiating partner. (Reporting by Lesley Wroughton; Editing by Jeffrey Benkoe)