Toyota Motor Corp. has terminated its business and capital partnership with Tesla Inc. by selling its stake in the U.S. electric car maker, sources said Saturday.

Toyota's decision suggests Japan's largest automaker sees no need to team up with Tesla on EV development because it is stepping up efforts to develop them on its own, the sources said.

Toyota and Tesla surprised the world by announcing the alliance in May 2010. Toyota detailed a plan to acquire 3.15 percent of Tesla's outstanding shares for about ¥4.5 billion ($40.5 million) to promote the joint development of EVs.

Toyota made a sport utility EV with Tesla-made batteries, but it fell short of mass production.

According to the sources, Toyota sold part of its stake in Tesla in October 2014 and had unloaded the rest by the end of last year. A Toyota spokesperson described the move as "a part of a regular review of business alliances."

Among next-generation vehicles, Toyota is seen leading in the development of fuel cell and hybrid vehicles but is said to be lagging rivals in electric vehicles.

Last November, Toyota announced the launch of a new unit under its president tasked with strengthening EV development.