The administration of US President Donald Trump has started investigating what effects imports of commercial aircraft, engines and related parts are having on national security. The move could lead to new tariffs.



The Commerce Department recently revealed that the investigation began on May 1 on national security grounds. The probe is based on Section 232 of the Trade Expansion Act, which allows the president to restrict imports that threaten national security.



The Trump administration used the law to impose tariffs on steel and aluminum.



The department says it will look at whether suppliers are concentrated in certain foreign companies and how subsidies by foreign governments are affecting competitiveness in the aviation industry, along with other issues.



The probe is scheduled to be completed within 270 days.



New tariffs could impact Japanese companies, as they have a strong presence in the field of aircraft engines and parts.



Boeing says Japanese firms manufacture about 35 percent of the parts used in its mid-sized 787 Dreamliner airplanes.