Japan's auto industry body said Friday it is "gravely concerned" about U.S. President Donald Trump's recent launch of a national security investigation into imports of automobiles, a move carmakers fear could result in new tariffs.

"It is consumers themselves who would be penalized, through increased vehicle prices and reduced model options, in the event that trade-restrictive measures were to be implemented" as a result of the investigation, said Akio Toyoda, chairman of the Japan Automobile Manufacturers Association.

"Moreover, the business plans of automobile and auto parts manufacturers as well as imported vehicle dealers could be seriously disrupted, with potentially adverse impacts on the U.S. economy and jobs," said Toyoda, who is also president of Toyota Motor Corp.

The U.S. launched an investigation last month into whether automobiles, including trucks and automotive parts, pose a threat to national security, stirring concerns among Japanese and other foreign automakers about their future business plans.

The United States is the biggest market for Japanese carmakers. If Trump decides to restrict auto imports, Japanese manufacturers' shift of production to the United States could accelerate and hollow out the domestic industry, observers said.

The industry body underscored that Japanese automakers are contributing to U.S. economic growth and job creation and that the imported vehicles do not represent a threat to U.S. national security.

"JAMA member companies today operate 24 manufacturing plants and 44 research and development or design centers in 19 U.S. states, and in 2017 nearly 3.8 million vehicles were produced by American workers at those facilities," Toyoda said.

"JAMA deems that free and fair trade and a competitive climate in line with global rules benefit consumers in the United States and strengthen the sustainable growth of the U.S. auto industry and its economy," he said.