United Nations experts monitoring freedom of expression have expressed concern about the growing prevalence of "fake news" and propaganda - and alarm at public authorities denigrating the media as "lying" or "the opposition".
The experts highlighted the obligation of governments to foster freedom of expression and state that restrictions can only be imposed in accordance with international law, including to prohibit advocating hatred and incitement to violence, discrimination or hostility.
David Kaye, the UN special investigator on freedom of opinion and expression, said: "'Fake news' has emerged as a global topic of concern and there is a risk that efforts to counter it could lead to censorship, the suppression of critical thinking and other approaches contrary to human rights law."
The declaration identified general principles to deal with disinformation, "fake news" and propaganda, and it includes human rights standards, encourages the promotion of diversity and plurality in the media, and emphasises the roles of journalists, media outlets and digital intermediaries.
The declaration was signed by monitors of freedom of expression at the Organisation for Security and Co-operation in Europe, the Organisation of American States, and the African Commission on Human and Peoples' Rights.
The joint declaration does not name any countries or leaders, but it follows repeated outbursts by US President Donald Trump against "the fake news media" which he accuses of being "the enemy of the American people".
The declaration emphasised that "some forms of disinformation and propaganda may harm individual reputations and privacy, or incite to violence, discrimination or hostility against identifiable groups in society".
It encouraged the media and civil society to identify and raise awareness about "deliberately false news stories, disinformation and propaganda".
The declaration also expressed alarm at instances "where public authorities denigrate, intimidate and threaten the media, including by stating that the media is 'the opposition' or is 'lying' and has a hidden political agenda."
This "increases the risk of threats and violence against journalists, undermines public trust and confidence in journalism as a public watchdog, and may mislead the public by blurring the lines between disinformation and media products containing independently verifiable facts", the declaration says.
The experts stressed that governments have an obligation to foster an environment for freedom of expression including promoting, protecting and supporting diverse media.
The declaration criticised attempts by some governments to suppress dissent and control communications using repressive rules on the operation of media outlets and other measures.
It said prohibitions on the dissemination of information "based on vague and ambiguous ideas, including 'false news' or non-objective information', are incompatible with international standards for restrictions on freedom of expression".
The declaration called the blocking of entire websites, IP addresses, ports or network protocols by a government "an extreme measure which can only be justified where it is provided by law and is necessary to protect a human right or other legitimate public interest".