President Donald Trump and China's President Xi Jinping meet business leaders at the Great Hall of the People in Beijing, China, November 9, 2017.

Chinese and U.S. teams ended trade talks in Beijing on Wednesday that lasted longer than expected and officials said details will be released soon, raising hopes an all-out trade war that could badly disrupt the global economy can be avoided.

The talks were extended into an unscheduled third day, showing both sides were "serious," China's Foreign Ministry said.

Share prices jumped in Asia and markets in Europe and the United States were expected to follow suit as the lengthened talks fueled optimism that the world's largest economies were inching toward an agreement.

Ted McKinney, U.S. Under Secretary of Agriculture for Trade and Foreign Agricultural Affairs, said the U.S. trade delegation would return to the United States later on Wednesday after a "good few days."

"I think they went just fine," McKinney said of the talks. "It's been a good one for us," he told reporters at the delegation's hotel, without elaborating.

Speaking at a daily news briefing, Chinese Foreign Ministry spokesman Lu Kang confirmed both sides had agreed to extend the talks beyond Monday and Tuesday as originally scheduled.

Asked if that meant they were difficult talks, Lu said: "I can only say that extending the consultations shows that the two sides were indeed very serious in conducting the consultations."

This week's meetings are the first face-to-face talks since U.S. President Donald Trump and Chinese President Xi Jinping agreed in December to a 90-day truce in a trade war that has roiled global financial markets.

The extra day of talks came amid signs of progress on issues including purchases of U.S. farm and energy commodities and increased access to China's markets.

However, people familiar with the negotiations told Reuters on Tuesday that the two sides were further apart on Chinese structural reforms that the Trump administration is demanding in order to stop alleged theft and forced transfer of U.S. technology, and on how Beijing will be held to its promises.

If no deal is reached by March 2, Trump has said he will proceed with raising tariffs to 25 percent from 10 percent on $200 billion worth of Chinese imports, at a time when China's economy is slowing significantly. Beijing has retaliated in turn to U.S. tariffs.

But as meetings wound down in Beijing on Tuesday evening, Trump tweeted: "Talks with China are going very well!"

The U.S. team is led by Deputy U.S. Trade Representative Jeffrey Gerrish, and includes under secretaries from the U.S. Departments of Agriculture, Commerce, Energy and Treasury, as well as senior officials from the White House.

Vice Commerce Minister Wang Shouwen heads the vice ministerial level talks for China, though Vice Premier Liu He, a top economic adviser to Xi, made an appearance at a meeting on Monday.

China is keen to put an end to its trade dispute with the United States but will not make any "unreasonable concessions" and any agreement must involve compromise on both sides, state newspaper the China Daily said on Wednesday.

The paper said in an editorial that Beijing's stance remains firm that the dispute harms both countries and disrupts the international trade order and supply chains.

In what is widely seen as a goodwill gesture, China on Tuesday issued long-awaited approvals for the import of five genetically modified crops, which could boost its purchases of U.S. grains as farmers decide which crops to plant in the spring.

On Monday, Chinese importers made another large purchase of U.S. soybeans, their third in the past month.