Toyota Motor Corp. has sold its stakes in the J-Phone group to the mobile phone operator's parent, Japan Telecom Co., to clarify its commitment to rival carrier KDDI, Toyota officials said Monday.

The leading automaker sold its stake in J-Phone Communications Co.'s three operating subsidiaries -- J-Phone East Co., J-Phone Central Co. and J-Phone West Co. -- for as much as 45 billion yen.

Toyota said it wants to concentrate on its tieups with KDDI, Japan's second-largest carrier, to promote the development of intelligent transport systems that integrate communications technologies with vehicle traffic.

Toyota owns 13.3 percent of KDDI and is the company's second-largest shareholder after ceramics manufacturer Kyocera Corp.

In its strategy to develop computerized car systems, the No. 1 automaker has been actively investing in telecommunications companies and had stakes of 1.97 percent in J-Phone East, 1.98 percent in J-Phone Central and 5.01 percent in J-Phone West.

Toyota reportedly sold the shares for between 40 billion yen and 45 billion yen, although the company would not confirm the proceeds.

Japan Telecom, meanwhile, said Friday that it has agreed to sell 5 percent stakes in each of the three firms to British Telecommunications PLC for 68 billion yen in total.

Japan Telecom holds a 54 percent direct equity interest in J-Phone's holding company, which oversees the three regional firms, while British Telecom owns 20 percent and rival British-based Vodafone 26 percent.

Japan's cellphone market, led by NTT DoCoMo, is booming, with 60 million people, or about half of the population, owning one.