As pressure intensifies for Toyota’s chief to testify before Congress about the automaker’s safety lapses, Japanese political leaders and experts worry that the problem — if handled poorly — could damage ties between the two nations.

There was an uneasy calm on Thursday when a Republican in the House of Representatives said he would support issuing a subpoena to compel Toyota President Akio Toyoda to appear before congressional committees later this month to examine the company’s string of safety problems.

Toyota said Mr. Toyoda is expected to visit the U.S. in early March, but the company declined to confirm Japanese media reports that he would attend the Washington hearings. Toyota’s North American head, Yoshimi Inaba, will appear before the committees, the company said.

Even before the world’s biggest automaker announced its latest recall on Tuesday of nearly 440,000 Prius and other hybrids, bringing its global total to 8.5 million vehicles for faulty gas pedals and brakes, Foreign Minister Katsuya Okada expressed concern about that the problem could become a political headache.

Further underscoring Toyota’s woes, the automaker said on Friday it is recalling about 8,000 Tacoma pickup trucks from the 2010 model year to fix a problem with the front propeller shaft that could cause the vehicle to lose control.

“I’m worried,” Okada said last Friday. “It’s not just the problem of one company but a diplomatic issue,” noting that the fiasco comes at a particularly difficult time for the automobile industry, including General Motors Corp.’s bankruptcy filing.

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