Japan is considering a partial lifting of its ban on arms exports so it can sell weapons parts to the United States as it prepares for joint development of a missile-defense system, government officials said Thursday.

"It's an issue to consider in the future," Chief Cabinet Secretary Yasuo Fukuda told a news conference.

"There is a debate over whether we can simply say we cannot offer our knowhow, products or parts (to the United States) after (jointly) conducting research and development" of a missile-defense system.