SHANGHAI (Reuters) - As White House officials fanned out to talk up what U.S. President Donald Trump called “an incredible deal” with China to hit pause in their trade war, Beijing has said little on a pact that cheered markets but left many questions unanswered.

FILE PHOTO: Shipping containers are being loaded onto Xin Da Yang Zhou ship from Shanghai, China at Pier J at the Port of Long Beach in Long Beach, California, U.S., April 4, 2018. REUTERS/Bob Riha Jr.

China’s foreign ministry, the only government department that holds a daily briefing foreign media can attend, has repeatedly referred questions on details to the commerce ministry, which has yet to say anything.

The commerce ministry is due to hold its weekly news briefing on Thursday.

A lack of detail from the Chinese side has left investors and analysts wondering if Trump’s exuberance is warranted, and if details touted by the White House but left out of Chinese reporting on the agreement are in question.

One Chinese official told Reuters officials were “waiting for the leaders to return” before publicizing details. President Xi Jinping and his most senior officials, including the commerce minister and the country’s two top diplomats, are in Portugal, and due back in China on Thursday.

The White House said China would agree to purchase a not yet agreed, but very substantial, amount of farm, energy, industrial, and other products from the United States.

It also said China had agreed to start buying farm products from U.S. farmers immediately.

China has made no direct mention of specific goods it will buy. Washington, but not Beijing, has also said China will cut import tariffs on American cars.

Beijing’s decision to keep things vague, for now, may reflect a desire to avoid being seen as having capitulated under pressure - the sides have 90 days to reach a deal - or may be a hedge against Trump’s unpredictability, analysts said.

“Apparently, the Chinese government doesn’t want its people to consider the agreement as a failure for China,” said Fang Kecheng, a Chinese media researcher at the University of Pennsylvania.

“The 90-day limit sounds like an ultimatum given by the strong actor to the weak actor,” added Fang, a former journalist for the publication Southern Weekly.

The U.S. embassy in Beijing posted a Chinese version of the White House’s readout of the meeting on the popular WeChat platform on social media, but reposting it was not possible.

China’s ambassador to the United States brushed off questions about the different accounts of the Trump-Xi meeting.

“I think that if you put the two press releases together, you can see what basically happened,” Cui Tiankai told Reuters in Washington on Monday after returning from Buenos Aires, where he had joined Xi’s delegation.

Cui added that negotiators would actually have less than 90 days to reach a deal because of holidays in both countries over the next three months.

MESSAGE MANAGEMENT

Behind Beijing’s apparent caution may also be a whiff of fear that the truce might not last, said Andrew Gilholm, of the consultancy Control Risks.

“They don’t want to look like they’ve gone across the Pacific offering concessions to placate Trump, and then a few weeks later escalation resumes,” he said.

To be sure, many tech-savvy Chinese were aware of the news, with some expressing unhappiness online about a lack of detail from state media.

However, a brokerage report speculated that a three-percent jump in Chinese stocks on Monday was partly stoked by enthusiasm based on optimistic but vague reporting in Chinese newspapers.

China’s reticence contrasted with the parade of U.S. officials talking about the deal on Monday, including Treasury Secretary Steven Mnuchin and White House Economic Adviser Larry Kudlow.

That may reflect differences in political culture more than anything, said Luwei Rose Luqiu, a journalism professor at Hong Kong Baptist University.

For meetings such as the Trump-Xi dinner, the initial official news report is typically drafted by the foreign ministry and approved by the General Office of the ruling Communist Party’s Central Committee, she said.

More often than not, such statements are short on details, said Luqiu, who covered meetings between Chinese and foreign leaders during 20 years as a reporter with Hong Kong’s Phoenix TV.

“Every time we covered this kind of bilateral meeting we had no detailed information from the Chinese side,” she said, adding that Chinese media were only allowed to publish the reports of state news agency Xinhua.

“This is China’s political culture.”