Thousands of UK riot police on Wednesday stood ready to deal with more potential outbreaks of violence, which erupted more than a week ago after three children were murdered.

Far-right groups have planned demonstrations in more than 30 locations, with immigration lawyers and buildings hosting asylum seekers set to be the primary targets, according to posts on messaging app Telegram leaked to the British media.

The government has said 6,000 specialist police are being readied to deal with England's worst disorder in over a decade, which has seen hundreds arrested and more than 100 charged.

The violence broke out after three girls, aged nine, seven and six, were killed and five more children critically injured during a knife attack at a Taylor Swift dance class in Southport, north west England.

False rumours initially spread on social media saying the attacker was a Muslim asylum seeker. The suspect was later identified as 17-year-old Axel Rudakubana, born in Wales. UK media reported that his parents are from Rwanda.

Despite the police statement, initial disturbances in Southport centred around a local mosque, and widespread violence has rocked England and Northern Ireland since.

Prime Minister Keir Starmer late Tuesday warned anyone involved would face "the full force of the law", including those inciting violence online.

Starmer, a former chief state prosecutor, said he expected "substantive sentencing before the end of this week" for the rioters, after chairing his second emergency meeting in as many days on Tuesday.

"That should send a very powerful message to anybody involved, either directly or online," he added in televised comments.

The unrest, Britain's worst since the 2011 London riots, has led a number of countries to warn its citizens about the dangers of travelling in the United Kingdom.

Rioting in several cities has seen demonstrators throw bricks and flares at police officers, burn cars and attack mosques and at least two hotels that have been used as accommodation for asylum seekers.

Scores of alleged perpetrators were hauled before judges on Tuesday, with some entering guilty pleas.

A 19-year-old man became the first person to receive a prison sentence related to the unrest when he received a two-month term Tuesday, PA Media reported.

Another man was convicted after he admitted assaulting a police officer outside a hotel housing asylum seekers in Rotherham, northern England, on Sunday.

A 15-year-old boy pleaded guilty to committing violent disorder in Liverpool on Saturday after he was identified from a TikTok video, while a man in Leeds admitted posting threatening words on Facebook to stir up racial hatred.

The government, only one month old, has vowed to take a tough line on the unrest.

"99.9% of people across the country want their streets to be safe and to feel safe in their communities, and we will take all necessary action to bring the disorder to an end," Starmer said Tuesday.

Justice minister Heidi Alexander told BBC Radio 4 that the government had freed up an extra 500 prison places.

Police have blamed the disorder on people associated with the now-defunct English Defence League, a far-right Islamophobic organisation founded 15 years ago, whose supporters have been linked to football hooliganism.

The rallies have been advertised on far-right social media channels under the banner "Enough is enough".

Interior minister Yvette Cooper said "there will be a reckoning" for perpetrators, adding that social media put a "rocket booster" under the violence.

Tech billionaire Elon Musk escalated a dispute with the UK government Tuesday by likening Britain to "the Soviet Union". A spokesperson for Starmer had said there was "no justification" for Musk's earlier comment that a British "civil war is inevitable".