US President Donald Trump is the "worst perpetrator" of false information on the internet, according to the UN Special Rapporteur on Freedom of Expression and Opinion.
David Kaye said everybody was struggling on how to deal with disinformation and part of the problem is the governments are the "real offenders" of fake news.
"Governments are putting out false information. I mean, in my own country, the United States, the worst perpetrator of false information is the President of the United States," Kaye told a website on Wednesday.
The problem of fake news emanating from the governments should be covered by journalists, he was quoted as saying by the Politico.
He said the companies can help with "technical things" where they can more and more treat spam and decrease the number of accounts that are bots.
"The platforms, I think, can do things that are more technical as long as they are not evaluating content. There are things they can do. They can't just zap it and say, This is fake news, it's off the platform," Kaye said.
"They can do things like identify how long is this Twitter account that's tweeting all of this information, how long has it been in effect? Was it created three hours ago? Well then, maybe it should be restricted. You know, how many followers does this one have? Are those followers bots?" he said.
Platforms should focus on reducing spam and bot accounts rather than on policing content, Kaye said, adding that bots are "tricky, because there are good bots and bad bots".
"There are things that everybody needs to be doing. Civil society has a role to play in this, too. If organisations are not doing the work themselves, they should be working with fact-checking organisations and others to try to identify which are the bad actors out there," he said.
President Trump has frequently derided unfavourable media reports as "fake news" and attacked journalists as "enemies of the people".