Japan will work together with other countries to submit a resolution as early as next spring to revise the United Nations Charter and reform the international body, according to Kenzo Oshima, Japanese ambassador to the U.N.

The four nations -- Japan, Germany, India and Brazil -- campaigning to expand the U.N. Security Council will be the "core members" that submit the resolution, Oshima told The Japan Times in an interview Friday.

"Common sense tells us that it will be submitted after March and before leaders of member states meet in September," Oshima said. U.N. Secretary General Kofi Annan is expected to compile a report on U.N. reform in March.