China finds it “hard to understand” why the United States is not sending senior government officials to a major import expo in Shanghai next month, the foreign ministry said on Thursday.

The world’s two biggest economies are locked in an escalating tariff row, with President Donald Trump having railed against China for what he sees as intellectual property theft, entry barriers to U.S. business and a gaping U.S. trade deficit.

Set to run from Nov. 5 to Nov. 10, the China International Import Expo will bring together thousands of foreign and Chinese companies, aiming to boost imports, allay foreign concern about China’s trade practices and show readiness to narrow trade gaps.

But the United States does not plan to send senior government officials to the fair, a U.S. embassy spokesman said on Wednesday, urging China to end what he called harmful and unfair trade practices.

Speaking at a daily news briefing, Chinese foreign ministry spokeswoman Hua Chunying said that it was the right of the United States to send whoever they wanted, adding:

“The United States, on the one hand, asks China to open its markets to U.S. products and services, yet on the other hand, the United States is not willing to send anyone to come when we open the door and invite people from all over.”

“This way of speaking and acting, I think everyone will believe, as I do, is extremely contradictory and hard to understand,” she said.

The import fair shows that China is willing to open its doors to other countries and share the benefits of Chinese development, Hua added.

More 130 countries and 2,800 companies have decided to take part, including 180 U.S. companies such as Microsoft Corp, Disney and Intel Corp, she said.

“Many U.S. companies have said to China that they wish to make full use of this expo to increase cooperation between Chinese companies and regions and U.S. companies and regions and to create a more effective platform for this,” Hua said.

China has said British trade minister Liam Fox will attend, while diplomats say most major trading partners will send delegations, including some that have been critical of its trade practices, such as Australia, Canada, France and Germany.

President Xi Jinping announced the import expo in early 2017 and is expected to speak at its opening.

However, some critics have dismissed the event, which China plans to hold every year, as largely a propaganda effort.