WASHINGTON—The Trump administration is considering launching trade actions to protect the U.S. aluminum, semiconductor and shipbuilding industries, while at the same time ramping up free-trade talks with the European Union, Japan and the U.K., Commerce Secretary Wilbur Ross said in an interview Tuesday.

Mr. Ross also left open the possibility that the U.S. government might intervene to help prop up Westinghouse Electric Co., the nuclear-reactor company thatfiled for bankruptcy protection in the U.S. last month, and may also try to block any new foreign entities from investing in the firm. Westinghouse is a unit of Japan’sToshiba Corp.

The US President Donald Trump has turned to Mr. Ross to play a lead role shaping his “America First” trade policy, and the 79-year-old billionaire investor was speaking after having overseen two major trade actions over the past week: launching a probe intocurbing global steel imports because of national-security concerns and moving to impose tariffs on Canadian lumber products over allegedly unfair subsidies.

Mr. Ross made clear in the interview that he saw those actions as just the beginning of a more aggressive trade-enforcement strategy in the coming months.

At the time he launched the steel probe last week, the administration named six “core industries” for its trade agenda—steel, aluminum, vehicles, aircraft, shipbuilding and semiconductors. Mr. Ross said that semiconductors, shipbuilding and aluminum could qualify for protection under the little-used Section 232 of a 1962 U.S. trade law, which authorizes the government to erect trade barriers to protect national security.