Ofcom has told social media firms - which have been blamed for stoking the unrest sweeping parts of the UK - that there is "no need to wait" to make their platforms safer.
In an open letter, external, the media regulator said there was an "increased risk" of the sites being used to "stir up hatred" and "provoke violence".
Ofcom is due to get tougher powers under the Online Safety Act, which has become law, but has not yet come into force.
But it said under existing regulations, video-sharing platforms such as TikTok and Snap "must protect their users from videos likely to incite violence or hatred".
But many platforms which allow people to upload video - such as YouTube and Elon Musk's X - do not need to follow these rules, external.
Fact-checking organisation, Full Fact, told the BBC tougher action was needed sooner.
"Online misinformation is a clear and present danger spilling across into unrest on UK streets in real-time", said Azzurra Moores, the organisation's policy manager.
"We can't afford to wait weeks and months for bolder, stronger action from Ofcom and the government."
In the letter, Ofcom's director for online safety Gill Whitehead said the regulator would publish its final codes of practice and guidance for the law by the end of the year.
But she asked the companies to act now, rather than waiting for the new law to come into effect, which may not be until 2025.
Prof Lorna Woods, of the University of Essex, who helped shape the Online Safety Act, said Ofcom was "in a difficult place", because of the need to wait for its enhanced powers.
She also pointed out even the new legislation had its limitations.
"If the Act were fully in force, it wouldn't catch all the content," she told the BBC.
"So while organising a riot would be caught, some of the dog whistling tactics and disinformation would not be.
"This was a concern from the last Government not to regulate non-criminal speech where adults were concerned."
The role that social media is playing in the disorder being seen in England and Northern Ireland is coming under increasing scrutiny,
The government said social media platforms "clearly need to do far more" after it emerged a list purporting to contain the names and addresses of immigration lawyers was being spread online.
The Law Society of England and Wales said it was treating the list as a "very credible threat" to its members.
Telegram, where the list appears to have originated, told the BBC its moderators were "actively monitoring the situation and are removing channels and posts containing calls to violence". It said such "calls to violence" were explicitly forbidden in its terms of service.
Earlier this week, the prime minister became embroiled in an online spot with Elon Musk, after the tech billionaire responded to the disorder by writing on X that "civil war" in the UK was "inevitable."