Tokyo and Washington signed an amendment Friday to a bilateral agreement governing reciprocal provision of logistics support, supplies and services between the Self-Defense Forces and the U.S. forces stationed in Japan.

The amendment to the Acquisition and Cross-Servicing Agreement allows the SDF and the U.S. forces to share ammunition for the first time, though the provision is limited to cases in which they jointly defend Japan from a foreign attack.

The government had excluded ammunition and weapons from the list of goods that can be shared between the SDF and the U.S. for fear that it could violate Japan's self-imposed ban on arms exports, a rule Tokyo introduced under its Constitution.