SHANGHAI/BEIJING (Reuters) - China is clearly angry about Washington’s hard line on trade, but has controlled coverage of the row in its media, limiting open commentary and banning attacks on U.S. President Donald Trump, several sources with knowledge of the matter said.

FILE PHOTO: U.S. President Donald Trump welcomes Chinese President Xi Jinping at Mar-a-Lago state in Palm Beach, Florida, U.S., April 6, 2017. REUTERS/Carlos Barria/File Photo

Beijing has issued unusually strict rules limiting coverage of the trade war because of worries that unrestrained reporting could spark instability or roil its already jittery financial markets, according to sources within Chinese state media.

“When exposing and criticizing American words and actions, be careful not to link it to Trump and instead to aim it at the U.S. government,” said a memo based on a set of directives issued verbally by government officials that was circulated to reporters at a state-run news outlet and seen by Reuters.

Media outlets must help “stabilize the economy, growth, employment, stabilize foreign trade, investment, finance, stabilize the stock market, the foreign exchange market, the housing market, and basically stabilize the peoples’ thinking, hearts and expectations”, it said.

A person who works at a leading Chinese news website said the rules issued last week were “the most strict yet”.

The website was told to post only stories about the trade conflict by state news agency Xinhua, rather than publishing its own. It was also ordered to keep the topic out of the top few headlines and closely manage comments about it, according to the source.

The website’s smartphone app was no longer permitted to send push notifications on the subject to users, and the website was forbidden from setting up special pages about the dispute.

Like other Chinese media workers who spoke with Reuters for this story, the source declined to be identified by name due to the sensitivity of the topic and because he was not authorized to speak publicly about it.

Editors at several leading state-media outlets, including the China Daily, the Global Times and Xinhua, were not made available after Reuters requested interviews. The information office of the State Council, or cabinet, did not immediately comment on the state’s efforts to censor news of the trade row.

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It was not immediately known if Beijing’s attitude would change after the United States threatened further import duties on Chinese goods on Tuesday in a sharp escalation of the conflict between the world’s two biggest economies.

To be sure, there have been vitriolic editorials in key Chinese newspapers as the trade tensions have simmered.

In recent weeks, state media have criticized U.S. behavior as reckless, hegemonic, delusional, and accused the Trump administration of harboring “blood lust” and behaving like a “gang of hoodlums”.

REVEALING CARDS

But the attacks have been general - there has been little mention of Trump, for instance - and few details on how China will be affected.

Two sources at separate state-run news organizations said they had been instructed not to mention the impact of the trade war on Chinese companies in their coverage.

At one large state news organization, a fourth source said journalists had been instructed to report on Chinese company news with caution because some were already feeling the effects of the trade spat.

Reporters at the news outlet, a key government mouthpiece, were directed not to stir up negative emotions or “reveal the cards” of Chinese importers, the source said.

In disputes with South Korea and Japan in recent years, Beijing has taken a more aggressive stance and at times encouraged public anger.

In 2012, state media tacitly supported anti-Japan protests during a spat over disputed islands, and last year the Communist Youth League helped target South Korean brands on social media amid a row over Seoul’s decision to allow the United States to install an advanced missile defense system on the Korean peninsula.

But the power imbalance in the China-U.S. trade dispute and the potential for real economic discomfort have led the control-obsessed leadership to adopt a softer approach, analysts said.

“They know the seriousness of the situation and the possible consequences, and they don’t want the media coverage to bring any kind of extra damage,” said Li Xigen, a professor in the department of Media and Communications at City University of Hong Kong.

“Later, as the situation gets worse, if the people are actually affected with their jobs, with prices ... that may become real anger, and if the media do anything to stir up that kind of anger it will cause some kind of very bad consequences.”

The trade war does not appear to be a hot item on China’s tightly-controlled social media. Media sources said authorities were censoring anything found objectionable, minimizing the prospect that any outcry on social media platforms could spur a backlash against U.S. brands.

Wang Jiangyu, a trade expert at the National University of Singapore, said attacking U.S. firms could backfire.

“China might need to restrict the market access of American companies. But to purge American companies that are already operating in China might be a very bad idea. Those companies generate jobs and revenue for China. Most Apple products are made in China,” he said.

“To do something to harm American firms that are already operating in China would be very stupid.”