BEIJING — Europe cast itself as a peacemaker here Monday, with senior officials calling on the United States and China to mend their commercial relationship and avoid a trade war that could drag on for years.

“There is still time to prevent conflict and chaos,” said European Council President Donald Tusk, speaking at a summit between China and the European Union.

His plea came a week after President Trump renewed his threat to impose tariffs on an extra $200 billion worth of Chinese goods, or nearly half of what the United States imported last year from China. The levies could take effect as early as September. 

The Beijing summit convened hours before Trump spoke with Russian President Vladimir Putin in Helsinki — a fraught meeting further complicated by the United States’ investigation into Russian meddling in the 2016 U.S. presidential election. 

Tusk condemned Trump’s swipes at European allies last week amid rising geopolitical tensions, and he urged world leaders in China on Monday to settle their economic disputes by reforming the World Trade Organization, a body that all parties have agreed needs improvement. 

Washington officials have said they resorted to tariffs because the WTO can take years to resolve conflicts, prolonging what they see as financial suffering from unfair trade practices. Trump has slammed “bad deals” with China, Mexico, Canada, the European Union and Japan, among other nations.

“We are all aware of the fact that the architecture of the world is changing before our very eyes,” Tusk said Monday at Tiananmen Square. “And it is our common responsibility to make it a change for the better.”

Beijing officials seemed less inclined to send a message to the United States. 

“Our summit is not directed at any third country,” Premier Li Keqiang said at a news conference, departing from the more fiery rhetoric of last week, when a Ministry of Commerce statement blasted the United States for “dragging the world economy into danger.”

But Beijing lodged a WTO complaint against the United States on Monday in response to 10 percent tariffs on Washington’s week-old list of Chinese imports, which hit consumer products such as televisions, bedsheets and air conditioners.

And in a joint statement Monday, China and the European Union denounced “protectionism and unilateralism” and unveiled plans to form a working group tasked with helping the WTO run more smoothly.

“Everyone should sit together to discuss how to perfect it and how to strengthen its authority,” Wang Shouwen, China’s vice commerce minister, said last month at a news conference.

The trade war between the United States and China officially launched July 6, when Trump slapped duties on $34 billion worth of mostly industrial Chinese goods, and Beijing responded by posting tariffs on an equal amount of American imports.

Trump has said he wants to narrow America’s $376 billion trade deficit with China and has accused the country of stealing U.S. business secrets. (Foreign companies often must partner with local firms to access the Chinese market.)

Although European leaders have condemned Trump’s trade strategy, they have also criticized China’s commercial environment for outsiders.

A recent report from the European Union, cited by the Associated Press, said Beijing erected more import and investment barriers than any other nation last year, making it harder for electronics and cybersecurity companies to do business here. 

However, some European businesses have lately found easier paths into the Chinese market — a sign China is wooing other trade partners as it prepares for a long battle with the United States, analysts say.

Earlier this month, German chemical company BASF received a green light to build a new $10 billion plant in the southern province of Guangdong after just three months of negotiations, according to two people close to the deal who were not authorized to speak to the media. 

That process usually takes years, they said.

The company was also allowed to join the Chinese market without a local business partner, another rarity in China. 

“China is realizing in order to make strides in industry and ambition it needs to lock into the global supply chain as smoothly as possible,” said Mats Harborn, president of the European Union Chamber of Commerce in China. “No one in this world can do it on their own.”

Correction: A previous version of this story misstated the value of the $34 billion worth of Chinese goods President Trump imposed tariffs on July 6.

Luna Lin and Amber Wang contributed to this report.