A U.S. government spokeswoman on Wednesday welcomed Japan's decision to ease a decades-old self-imposed ban on arms exports under the war-renouncing Constitution.

"We believe this is a good step. We welcome this step," State Department spokeswoman Marie Harf told reporters, referring to the decision Tuesday, which enables Japan to conditionally develop arms with the United States and other allies and access new arms technology.

"What the change really does is allow Japan to modernize its defense industry and processes so it can participate in the 21st-century global acquisition marketplace," she said.