BEIJING — China tried to step up pressure on Washington in their growing tariff war Thursday by suggesting U.S. companies lobby American leaders, while a Korean union warned President Donald Trump’s threat of higher auto import duties could lead to job losses in Alabama.

Beijing and Washington have yet to resume negotiations over the dispute that led to tariff hikes on each other’s goods last week, said a spokesman for the Chinese Commerce Ministry.

“We hope American companies do more to lobby the U.S. government and work hard to safeguard their own interests,” said Gao Feng at a news conference.

While some U.S. companies and lawmakers have criticized Trump’s tactics, GAO’s statement was an unusually direct attempt to rouse domestic American opposition. Beijing frequently rejects foreign comments about its own policies as improper interference in its affairs.

Gao gave no details. His remark about lobbying was missing from an official transcript on the ministry’s website, suggesting officials recognized its potential sensitivity.

The Trump administration imposed a 25 percent tariff on $34 billion of Chinese goods Friday in response to complaints Beijing steals or pressures companies to hand over technology. Beijing responded by imposing similar duties on the same amount of imports from the United States.

Washington announced a second possible round of tariff hikes Tuesday targeting a wider range of $200 billion of goods. Beijing vowed “firm and forceful measures” in response, but China’s lopsided trade balance means it cannot match the full scale of American tariff hikes. That has prompted concern regulators might expand retaliation to trying to hamper operations of American companies in China.

Chinese leaders have tried to deflect criticism by pointing to the benefits of trading with the world’s second-largest economy, a theme Gao repeated Thursday. He noted Tesla Inc.’s announcement this week of plans to build a factory in Shanghai.

China has a “great potential consumer market that is steadily more open,” said Gao. “We will continue to improve the business environment.”

As for negotiations, he said, “the two sides have not been in touch about restarting talks.”

At the heart of the dispute is Chinese policies including “Made in China 2025,” a sweeping strategy that calls for state-led development of local champions in robots, biotech and other fields. American officials say such development strategies are based on improperly obtained technology and might threaten U.S. industrial leadership.

Communist leaders have resisted pressure to roll back strategies they see as a path to prosperity and global leadership.