UNITED NATIONS (Reuters) - U.N. Secretary-General Antonio Guterres on Friday accused social media platforms and those who advertise on them of being "complicit" in accelerating extremism like antisemitism, racism, anti-Muslim bigotry, xenophobia, homophobia and misogyny.

"They are profit-driven catalysts for moving extremism from the margins to the mainstream," Guterres said during a speech to mark International Holocaust Remembrance Day.

"By using algorithms that amplify hate to keep users glued to their screens, social media platforms are complicit. And so are the advertisers subsidising this business model," he said.

Guterres has long expressed concern about the power of social media companies and has been calling for regulation to clarify responsibility and improve transparency. He appealed on Friday for them, along with governments, to "stop the hate".

"We know how easily hate speech turns to hate crime, how verbal violence breeds physical violence, how diversity and social cohesion are undermined – as are the values and principles that bind us together," Guterres said.

(Reporting by Michelle Nichols; Editing by Jan Harvey)