The US commitment to the defense of Japan is "ironclad," top US diplomat John Kerry vowed Monday as the two allies broadened their military cooperation revising their rules for the first time since 1997.

The US commitment to the defense of Japan is "ironclad," top US diplomat John Kerry vowed Monday as the two allies broadened their military cooperation revising their rules for the first time since 1997.

And amid tensions with China in the South and East China Seas, Kerry said the US commitment "covered all territories" administered by Japan "including the Senkaku islands."