Security was being strengthened at hundreds of mosques across the country amid fears that the places of worship may be targeted by anti-Islamic demonstrators, Muslim leaders said.

Disorder blamed on extreme-right agitators broke out in several English cities this week after Monday's knife attack at a Taylor Swift-themed dance party in Southport, in the northwest.

The disturbances were fuelled by misinformation online about 17-year-old suspect Axel Rudakubana who has been charged with murder and attempted murder over the stabbing rampage that has shocked Britain.

Prime Minister Keir Starmer accused "thugs" of "hijacking" the nation's grief to "sow hatred" and pledged that anyone carrying out violent acts will "face the full force of the law".

Several demonstrations are planned for the coming days, with some protests advertised online with the banner "enough is enough" and calling for participants to bring England flags.

Merseyside Police, responsible for Southport, said it was aware of potential future protests there and that "extensive plans and considerable police resources" were in place to deal with them.

South Yorkshire police said it knew of a planned protest in the town of Rotherham this weekend and that people may see "an increased police presence" across the whole county.

Officers in south Wales said a policing operation would be in place for "planned events being held in Cardiff" on Saturday.

The Police Service of Northern Ireland said it was aware of social media posts calling for roadblocks "using women and children" as part of a planned protest, as well as a march to an Islamic centre in Belfast on Saturday.

Suspected members of Islamophobic organisations threw bricks at a mosque in Southport on Tuesday night as they clashed with police.

Protests then rocked central London, and the northern cities of Hartlepool and Manchester late Wednesday. Police arrested more than 100 people outside Downing Street.

Zara Mohammed, secretary-general of the Muslim Council of Britain (MCB), told PA Media that mosques were bracing for the weekend by hiring paid security staff and checking CCTV cameras were working.

"There is really deep-seated anxiety amongst Muslim communities, particularly for this weekend," he said.

Rudakubana is accused of killing Bebe King, six, Elsie Dot Stancombe, seven, and Alice Dasilva Aguiar, nine. He has also been charged with 10 counts of attempted murder.