Japan and the United States said Friday they won't revise their defense cooperation guidelines until the first half of next year, keeping in step with Tokyo's efforts to legalize its use of collective self-defense.

The update, originally planned for the end of this year, will likely come in May or later, a Japanese official said, given that the Abe administration is expected to submit the security legislation to the Diet after nationwide local elections in April.

In a joint statement, Japan and the United States stressed the importance of ensuring that the revision will have substance, and strengthen the long-standing bilateral alliance to enhance deterrence. The statement was issued by the foreign affairs and defense chiefs of both nations.