Chinese President Xi Jinping and President Donald Trump greet attendees waving American and Chinese national flags during a welcome ceremony outside the Great Hall of the People in Beijing, China, on Nov. 9, 2017.

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.

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.