China on Thursday singled out dozens of companies from the United States, including Raytheon291bet, Boeing and Lockheed Martin, in a series of punitive trade measures that could ratchet up tensions between the two superpowers.

With weeks to go before President-elect Donald J. Trump takes the office with a promise to impose new tariffs and sanctions on China, Beijing is once again showing it is ready to strike back.

China’s Ministry of Commerce said it added 28 companies to an export control list to “safeguard national security and interests.” It also banned the export of so-called dual-use items, which have both civilian and military applications, to those companies. And it placed 10 companies on what it calls an “unreliable entities list” related to the sale of arms to Taiwan, preventing them from doing any business in China and prohibiting their executives from entering or living in the country.

Chinese authorities have taken similar — albeit narrower — actions in the past on these companies, most of which have a limited presence within China, said Andrew Gilholm, a China expert at the consulting firm Control Risks.

“Most of this is probably at the symbolic level because so many of these entities were already subject to sanctions,” he said. But, he added, “what we’re seeing is the widening scope and number of entities being added in a single listing.”

Among the companies called out by China were the leading American makers of defense systems, including Raytheon Missile Systems, Boeing Defense, Space and Security and Lockheed Martin Missiles and Fire Control. The companies did not immediately respond to emailed requests for comment.

“He’s going to end the chronic disease epidemic,” said Mr. Kennedy, who has for years expressed doubts about the safety of vaccinating children and has pushed conspiracy theories about the inner workings of federal health agencies. “And he wanted my help to do it.”

And if the job market cools more than expected or if inflation comes in weaker than expected, the Fed could reduce interest rates more rapidly.

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