Japan expressed concern Tuesday about a U.S. plan to research the development of small, low-yield nuclear weapons.
Chief Cabinet Secretary Yasuo Fukuda said the U.S. government has told Japan that the move is solely for research into small nuclear weapons, and that it would not lead to the development or use of such weapons.
"I believe it will not lead to the actual use of such weapons . . . we have confirmed this" with the U.S. side, he told a regularly scheduled news conference.
But Fukuda said Japan has nevertheless repeatedly conveyed its concern to the U.S.
"We have conveyed our message that we want (the U.S.) to consider concerns in Japan and the world over the fact that (the U.S.) may resume nuclear tests, which would have a negative impact on nuclear nonproliferation."
He said Japan seeks a world free of nuclear weapons.
Japan has said all nuclear weapons are unacceptable under any circumstances and has reminded the world about the dangers of using them.
Last week, the U.S. Congress approved a $27.3 billion spending bill for energy and water programs in 2004, including $6 million to research small, low-yield nuclear weapons.
The approval lifts a decade-old ban on research into such weapons.
Critics say the U.S. move may prompt others to follow suit, as such weapons, which are less devastating than their larger counterparts, might be seen as a usable adjunct to conventional arms.
Proponents meanwhile argue that new nuclear weapons are necessary to deter emerging nuclear powers.