Japan, the world's biggest importer of rare earth metals, plans to send a study group to Mongolia this month as it tries to diversify its supply sources.

The Ministry of Economy, Trade and Industry will send a group in mid-October to study rare earth deposits with Mongolia's government, Hiromitsu Sugawara, deputy director at the ministry's Northeast Asia division, said Monday. The two countries have also agreed to expedite talks for an economic partnership agreement and to develop coal and uranium projects.

METI will form a delegation from Japan Oil, Gas & Metals National Corp., which manages and explores Japan's strategic resources, and the National Institute of Advanced Industrial Science & Technology, Sugawara said by phone.

Trade minister Akihiro Ohata met Mongolian Prime Minister Sukhbaatar Batbold in Tokyo Sunday, a day after Prime Minister Naoto Kan and Batbold agreed to begin an effort to locate rare earth mines, Sugawara said.

China, which controls more than 95 percent of the global supply of the elements, imposed a de facto ban on exports to Japan last month, economy minister Banri Kaieda said on Sept. 28, as ties between the two nations soured over a maritime incident near the Japan-controlled Senkaku islets.

Chen Rongkai, a spokesman for China's Ministry of Commerce, said Sept. 28 that the nation hadn't imposed a ban. The Asahi newspaper reported a day later, citing unidentified Japanese companies, that the ban was lifted when the Chinese government began accepting customs applications.

Japan depends on China for 90 percent of its rare earth supplies, according to data from the trade ministry. The minerals are used in radar, high-powered magnets, laptop computer hard drives, auto catalytic converters, electric-car batteries and wind turbines.