The United Kingdom's prime minister met senior police officers on Thursday to discuss violence that has flared since a horrific attack on children on Monday that left three girls dead and several others fighting for their lives.

Keir Starmer said he wanted to thank officers for their hard work following the incident in the northwestern town of Southport, and discuss subsequent violent protests.

He is understood to be especially concerned about misinformation that claims the alleged Southport assailant was an immigrant and an Islamic extremist.

The rumors led to attacks on mosques and anti-immigrant protests and Starmer's spokesman told reporters: "While the right to peaceful protest must be protected at all costs, (the prime minister) will be clear that criminals who exploit that right in order to sow hatred and carry out violent acts will face the full force of the law."

The meeting followed disorder in central London on Wednesday night that saw more than 100 arrests. Violence also flared in the northeastern town of Hartlepool and in Manchester and Aldershot.

In a statement issued before Wednesday night's violence, Metropolitan Police Superintendent Neil Holyoak said it was "understandable" people had "strong feelings" about the alleged knife attack but that demonstrators would not be allowed to break the law. His comments followed a violent protest in Southport on Tuesday night that he said was "completely unacceptable" and "driven by misinformation".

Dal Babu, a former chief superintendent, said on BBC Radio 4's Today program: "People are setting up accounts, they're putting up false information. They don't really care around the accuracy of this information."

Mayor of London Sadiq Khan also criticized the violent protests, saying: "There is no place for criminality on our streets and I fully support the Met Police taking action against those intent on violence, causing disorder and spreading division in our city."

Ahead of Starmer's meeting with senior police officers, the 17-year-old suspected of carrying out Monday's knife attack appeared in court and was formally named.

Axel Muganwa Rudakubana has been charged with three counts of murder, 10 counts of attempted murder, and a charge of possession of a bladed article. He was remanded in custody until his next appearance at Liverpool Crown Court on Oct 25.

The charges follow an alleged knife attack at a Taylor Swift-themed holiday club that claimed the lives of 6-year-old Bebe King, 7-year-old Elsie Dot Stancombe, and 9-year-old Alice Dasilva Aguiar. Eight other children and two adults were also injured.

Merseyside Police also took the unusual step of confirming Rudakubana was born in the UK to Rwandan parents and does not have known links to Islam. They also said the attack is not thought to be terror-related.