WASHINGTON (Kyodo) -- U.S. Commerce Secretary Howard Lutnick said Sunday that a recently announced exemption of smartphones and other electronic devices from broad reciprocal tariffs is only a temporary measure, with those items eventually expected to fall under "semiconductor sectoral tariffs."

"They're included in the semiconductor tariffs, which are coming in probably a month or two," Lutnick told ABC News, noting they would be the same type of sector-based duties that were imposed on autos under the administration of U.S. President Donald Trump.

The remarks came after the U.S. Customs and Border Protection published on Friday a list of items excluded from the reciprocal tariffs that took effect starting April 5, such as computers and semiconductor-manufacturing devices, an area of export strength for Japan.

Trump said his administration is planning a national security trade investigation into semiconductors as well as the whole electronics supply chain.

"What has been exposed is that we need to make products in the United States, and that we will not be held hostage by other Countries, especially hostile trading Nations like China," he said on his social media platform.

Trump, who took office in January for the second time, has been rolling out massive duties on U.S. trading partners to rectify what he views as imbalanced trade.

As for reciprocal measures, Trump announced last week a 90-day pause on the implementation of steep tariffs targeting goods from dozens of trading partners, including Japan, but not for China, on which he raised duties to 125 percent.

The tech tariff exclusion is expected to temporarily avert price hikes of some tech products, such as Apple Inc.'s iPhones in the United States, of which many are manufactured in China.