Japan may be unable to negotiate a shorter grace period for the elimination of tariffs levied by the United States on Japanese vehicles in bilateral talks within the Pacific free trade initiative, sources close to the matter said Wednesday.

Such tariffs may be abolished after more than 20 years as part of the U.S.-led Trans-Pacific Partnership deal, they said.

That will be shorter than the 30 years that the United States proposed in negotiations last year, but far longer than the 10 years within which the U.S. government has agreed to remove its auto tariffs in a separate bilateral free trade pact with South Korea.