TOKYO Japan's Foreign Minister Yoriko Kawaguchi will travel soon, most probably late this month, to Iran and Afghanistan, Foreign Ministry Spokesman Norio Jattori told IRNA here Tuesday.

The details of the travel agenda, to be announced accordingly, are being prepared, Norio added.

Japan and Iran clinched a landmark deal during President Mohammad Khatami's visit to Tokyo in 2000, giving preferential negotiation rights to Japan for the development of the world's biggest undeveloped oil field in Azadegan in southern Iran.

The huge oil field is said to hold at least five to six billion barrels of recoverable crude oil and could pave the way for Japan's largest investment in Iran since the Islamic Revolution in 1979.

The Azadegan field has the potential to produce up to 400,000 barrels of crude oil per day -- more than 80 percent of the amount that Japan, now gets from Iran.

The Islamic Republic accounts for 11 percent of Japan's oil imports as the third largest oil supplier of that country.

Japan in return agreed to extend Iran a trade credit line worth three billion dollars over three years.