The German government has approved a draft law to fine social networks up to 50 million euros ($53m) if they fail to remove hateful postings and fake news reported by users quickly, prompting concerns over freedom of expression.
Wednesday's move comes as German politicians worry that a proliferation of fake news and racist content, particularly about refugees, could sway public opinion in the run-up to national elections in September.
"There should be just as little tolerance for criminal rabble-rousing on social networks as on the street," Justice Minister Heiko Maas said in a statement.
"It is clear that freedom of expression is of huge importance in our vibrant democracy... However, freedom of expression ends where criminal law begins."
He also said he would seek to push for similar rules at a European level.
Maas said a government survey showed Facebook deleted only 39 percent of content deemed criminal and Twitter only one percent, even though they signed a code of conduct in 2015, including a pledge to delete hate speech within 24 hours.
Organisations representing digital companies, consumers and journalists, accused the government of rushing a law to parliament that could damage free speech.
"It is the wrong approach to make social networks into a content police," said Volker Tripp, head of the Digital Society Association consumer group.
A spokesman for Facebook - which has 29 million active users in Germany, more than one-third of the total population - said the company was working hard to remove illegal content, but expressed concern at the draft law.
"This legislation would force private companies, rather than the courts, to become the judges of what is illegal in Germany," he said, adding that Facebook's partner Arvato would employ up to 700 staff in Berlin for "content moderation" by year's end.
A spokesman for Twitter declined to comment on the legislation, but said the company had made a number of changes in recent weeks, including adding new filtering options, putting limits on accounts it had identified as engaging in abusive behaviour, and stopping those users from creating new accounts.
Beyond hate speech and fake news, the draft legislation also covers other illegal content, including child pornography and "terrorism-related activity".
The draft law still requires approval from parliament.
The legislation would give social networks 24 hours to delete or block obviously criminal content. The companies would have seven days to deal with less clear-cut cases, with an obligation to report back to the person who filed the complaint about how they handled the case.
Failure to comply could see a company fined up to 50 million euros ($53m), and the company's chief representative in Germany fined up to five million euros ($5.3m).
Source: News agencies