The UK government said on Tuesday that 6,000 specialist police officers were ready to deal with far-right rioting that broke out following the murder of three children, and has now continued for seven consecutive days.
On Monday, six people were arrested and several police officers injured when they were attacked by rioters hurling bricks and fireworks in Plymouth, southern England.
Officers in Belfast, Northern Ireland, were attacked as rioters attempted to set fire to a shop owned by a foreign national.
Meanwhile, a group of men who gathered in Birmingham, central England, to counter a rumoured far-right demonstration, forced a Sky News reporter off air shouting: "Free Palestine". She was then followed by a man in a balaclava holding a knife.
Another reporter said he was chased by members of the group "with what looked like a weapon", while police said there had also been incidents of criminal damage to a pub and a car.
Riots have since flared up in several cities and towns, leading to hundreds of arrests.
Justice minister Heidi Alexander told BBC Radio 4 on Tuesday that the government had freed up an extra 500 prison places and drafted in 6,000 specialist police officers to deal with the ongoing violence.
"We will make sure that anyone who is given a custodial sentence as a result of the riots and disorder, there will be a prison place waiting for them," she said.
Mobs threw bricks and flares, attacked police, burnt and looted shops, smashed the windows of cars and homes and targeted at least two hotels housing asylum seekers in a number of cities at the weekend.
Prime Minister Keir Starmer on Monday convened and emergency meeting of ministers and police chiefs to discuss the unrest.
The government will "ramp up criminal justice" to ensure that "sanctions are swift", Starmer told the media after Monday's meeting.
The National Police Chiefs' Council (NPCC) said 378 people had so far been arrested and that others would be "brought to justice".
Clashes broke out in Southport on Wednesday, the day after three young girls were killed and five more children critically injured during the knife attack there.
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, which has very few Muslims.
That has not stopped mosques from being targeted by rioters.
The government has offered new emergency security to Islamic places of worship.
In Burnley, northwest England, a hate crime investigation was underway after gravestones in a Muslim section of a cemetery were vandalised with grey paint.
"What type of evil individual(s) would undertake such outrageous actions, in a sacrosanct place of reflection, where loved ones are buried, solely intended to provoke racial tensions?", local councillor Afrasiab Anwar said.
Interior minister Yvette Cooper told the BBC on Monday that "there will be a reckoning".
Cooper also said that social media put a "rocket booster" under the violence.
Starmer stressed that "criminal law applies online as well as offline".
On Tuesday, Alexander criticised Elon Musk, owner of X, after he claimed "civil war" in the UK was "inevitable".
"I think it is deeply irresponsible. I think everyone should be appealing for calm," she said.
Police have blamed the violence 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".
