WASHINGTON, May 29 (Reuters) - The United States has ordered a broad swathe of companies to stop shipping goods to China without a license and revoked licenses already granted to certain suppliers, said three people familiar with the matter.

The new restrictions - which are likely to escalate tensions with Beijing - appear aimed at choke points to prevent China from getting products necessary for key sectors, one of the people said.

Products affected include design software and chemicals for semiconductors, butane and ethane, machine tools, and aviation equipment, the people said.

Many companies received letters from the U.S. Department of Commerce over the last few days informing them of the new restrictions.

Firms that supply electronic design automation (EDA) software for semiconductors were sent letters last Friday that licenses would now be needed to ship to Chinese customers, two of the sources said.

The electronic design automation software makers include Cadence, Synopsys and Siemens EDA, a subsidiary of Siemens one said.

The two sources said the Commerce Department will review requests for licenses to ship to China on a case-by-case basis, suggesting the action was not an outright ban.

It is unclear whether the new restrictions are part of a broader strategy to create leverage for trade talks during a pause in the imposition of higher tariffs.

The Commerce Department said it is reviewing exports of strategic significance to China, while noting "in some cases, Commerce has suspended existing export licenses or imposed additional license requirements while the review is pending."

The White House did not immediately respond to a request for comment.

Shares of Cadence, which declined to comment, closed down 10.7% and shares of Synopsys fell 9.6%.

Siemens said it was assessing the impact of the new restrictions on exports of EDA software and will provide more information as soon as possible.

China's foreign ministry said in a response to Reuters' questions that such U.S. practices disrupted the stability of global supply chains and that Washington was weaponizing tech and trade issues to shut out and persecute China.

"There are no sanctions or pressure that can block the pace of China's development and progress, no bullying or coercion that can shake China's determination to achieve self-sufficiency," it said.

Synopsys' CEO Sassine Ghazi said in a call with analysts that the company had not received a letter nor had it heard from the Commerce Department's Bureau of Industry and Security, which enforces export controls.

"We are aware of the reporting and speculations, but Synopsys has not received a notice from BIS ... We have not received a letter," Ghazi said.

After the market closed, Synopsys reaffirmed its revenue forecast for 2025. Its shares and those of Cadence bounced back 3.5% in trading after the close.

Restricting Chinese firms' access to EDA tools would be a big blow to the industry as Chinese chip design customers heavily rely on top-of-the-line U.S. software. In April, Chinese state news agency Xinhua said Synopsys, Cadence and Siemens's Mentor Graphics together control more than 70% of the market share in China.

Chinese companies that have said they use Synopsys and Cadence software include design firm Brite Semiconductor, Zhuhai Jieli and semiconductor IP portfolio provider VeriSilicon.

VeriSilicon and Brite did not immediately respond to emails seeking comment. Calls to Zhuhai Jielei went unanswered.

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