NAGOYA, Japan—Toyota Motor Corp. and BMW AG said they will expand a technology-sharing pact, the latest sign of a deepening partnership between the two companies.

"By working with BMW we hope to speed up the development and diffusion of fuel cell vehicles, which has required significant investments in cost and time," said Takeshi Uchiyamada, Toyota's vice chairman and former head of research and development, said at a press conference in Nagoya Thursday. "This will work to strengthen both companies."

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