The Defense Agency on Friday requested 963 million yen in the fiscal 1999 budget to start a joint research program with the United States to develop a missile defense system.The budget is to cover the design and trial manufacture of missiles to be used for the Navy Theater Wide Defense system, the sea-based part of the U.S.-proposed Theater Missile Defense program, agency officials said.Earlier in the day, agency Director General Fukushiro Nukaga told a Cabinet Security Council meeting that research on a TMD system "is important in terms of our national defense policy, given the increasing proliferation of ballistic missiles and weapons of mass destruction."The TMD program aims to intercept ballistic missiles by firing counter-missiles deployed at sea and land that are linked with reconnaissance satellites. Chinese and Russian leaders Thursday expressed anxiety over Japan's decision. "We have just officially requested the budget. Further discussions (over participation in the U.S. program) will have to be made at the government as well as at the Defense Agency," Nukaga told reporters after the council meeting.Government sources said Tokyo will ask for "understanding" from neighboring nations by emphasizing that what Japan will do is just research -- whether to develop and introduce a missile defense system has yet to be decided.Aside from negative reactions from neighboring states, there are legal barriers to overcome before fully joining the TMD program. A 1969 Diet resolution bans the use of outer space for military purposes. The TMD program, which will use space-borne satellites and interceptor missiles that pass through space, is seen to violate the resolution.The government has also prohibited since 1976 the export of any goods that can be utilized for military purposes. That runs counter to the fact that the TMD system, if developed, will be deployed overseas by the U.S. military.Masahiro Akiyama, Defense Agency administrative vice minister, told reporters Thursday that the government will explain the "legal consistency" of joining the TMD program by December, when the Diet is expected to start deliberations on the budget.Agency sources said the agency insists it is just starting joint "research" and will leave open issues concerning Japan's participation in "development" of missiles, which will follow the at least five-year research period.