Social media, including Facebook, must proactively block content inciting hatred and prevent online campaigns which target minorities, such as those undertaken in Myanmar, the United Nations human rights chief said on Wednesday.

Zeid Ra’ad al-Hussein, U.N. High Commissioner for Human Rights, was speaking after U.N. experts accused Myanmar generals of “genocidal intent” and said Facebook had allowed its platform to be used to incite violence against Rohingya.

Facebook said on Monday it was removing several Myanmar military officials from the social media website and an Instagram account to prevent the spread of “hate and misinformation” after reviewing the content.

Zeid, whose spokesman said he has met with major tech companies in Silicon Valley, including Facebook and Google, in recent months, was speaking to a news conference before his four-year term ends on Aug. 31.

Zeid said he didn’t feel Facebook took the issue seriously at first but that the company’s attitude began to change after Yanghee Lee, U.N. special rapporteur on human rights in Myanmar, told a Geneva press conference in March that Facebook was being used in the country to spread hate speech.

“But it shouldn’t be because the press or the human rights community highlights the problem for them then suddenly to respond. They should be aware of it ahead of time,” he said.

“So I don’t think they should wait until the crisis begins. They should be thinking proactively about what steps they will take to mitigate that,” he added.

Facebook said on Monday that while it was too slow to act in the case of Myanmar, it was now making progress, with better technology to identify hate speech and improved reporting tools.

However, Zeid said there was a danger that social media could be over-regulated in a way that breaches human rights law including the right to freedom of expression.

Tech giants should “keep the broadest space available and open to the exercise of freedom of expression”, relying on international human rights law for regulation, he said.

U.S. President Donald Trump on Tuesday accused Google’s search engine of promoting negative news articles and hiding “fair media” coverage of him, vowing to address the situation without providing evidence or giving details of action he might take.

Trump’s attack against the Alphabet Inc. unit follows a string of grievances against technology companies, including Twitter Inc and Facebook, which he has accused of silencing conservative voices.

The U.N. rights chief said on Monday that U.S. President Donald Trump bears “a heavy responsibility” for how the media is portrayed and that his remarks could have a knock-on effect that could hurt journalists in other countries.

U.S. newspapers across the country ran editorials last Thursday defending freedom of the press in response to President Donald Trump calling some media organizations enemies of the American people.

“To label the press in this way is very worrisome,” U.N. High Commissioner for Human Rights Zeid Ra’ad al-Hussein said in a wide-ranging interview days before his four-year term ends.

“The President should be aware that a heavy responsibility lies on his shoulders when it comes to the way in which the media is being portrayed,” Zeid said, speaking to Reuters, Associated Press and Agence France Presse in his Geneva office.

“Because it also has a demonstration effect, other leaders in authoritarian settings will do same thing. We’ve seen now how they mimic President Trump and so what could already be a difficult situation in other countries becomes even more difficult for the press to operate and for journalists to uncover stories and for lawyers to do their work and for human rights defenders to do their work,” he added.

Trump’s comments reflect a view held by many conservatives that many media outlets distort, make up or omit facts because of a bias against them. The Republican president has said he supports the principle of press freedom, but has described much of what the media publishes as “fake news”.

VETOES, CRISES

Zeid has been outspoken about human rights violations, earning rebukes from the United States and its ally Israel, as well as China, Myanmar, Hungary, Syria, and his native Jordan.

On Monday, he criticised world powers in the U.N. Security Council – singling out the United States, Russia and China – for casting vetoes and preventing resolution of crises or their being referred to the International Criminal Court (ICC).

“And I think that has to change, in the end the organisation can collapse at great cost to the international community and to international peace and security,” Zeid warned.

“The threats to the system altogether are very real.”

On China, he called for access to the far western region of Xinjiang following reports by activists and independent U.N. rights monitors this month about mass detention of Muslim Uighurs.

China has rejected allegations raised by the U.N. panel that 1 million Uighurs may be held in internment camps in the restive region, but said that some people underwent re-education after being deceived by extremists.

“As with all countries, the request is let us in or else we will assume the absolute worst,” Zeid told Reuters.