Thousands of protesters countering the anti-racism demonstrations assembled in and around Parliament Square in London, despite the coronavirus restriction orders. The local police said they arrested more than 100 people on Saturday after the protesters clashed with officers.

That required "major" policing operation, the Metropolitan Police Service said, adding that they had encountered "pockets of violence directed towards our officers."

Television footage showed some agitators throwing punches, bottles and smoke bombs at officers as well as scuffling with rival protesters.

Police said they had arrested more than 100 peopled by 2000 GMT for violent disorder, assault on officers and possession of an offensive weapon. Six officers suffered minor injuries. Prime Minister Boris Johnson said "racist thuggery has no place on our streets" and that "anybody attacking the police would be met with full force of the law."

As footage of the disorder was shared widely on social media, he wrote on Twitter: "Racism has no part in the UK and we must work together to make that a reality."

'Guard our monuments'

A protest by the Black Lives Matter group planned for Saturday had been switched to Friday to avoid clashes with the far-right counter-demonstration.

Anti-racism group Hope Not Hate had warned before Saturday that hooligan gangs attached to some English football clubs also planning to attend Saturday's counter-protest.

Paul Golding, leader of fringe far-right political group Britain First, which has seen its members jailed for hate crimes and been banned from Facebook, was among the first to arrive at Parliament Square.

Golding, who was last month found guilty of an offence under the Terrorism Act, told the domestic Press Association news agency they had turned out to "guard our monuments."

Last week, the statue of slave trader Edward Colston was torn down amid the Black Lives Matter movement, inciting a debate raging over the monuments of those during Britain's imperialist history. Among those statues, one for Winston Churchill in London was daubed with the words "was a racist."

Former Conservative MP Nicholas Soames, Churchill's grandson, denounced the "very small, extremely explosive group of people" responsible for last weekend's vandalism.

"The idea that the hard right should stand guard over Churchill is absolutely repulsive," he told the Daily Telegraph, "It feels like a society that has lost its compass."

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Saturday, hundreds of people chanting "England, England," and describing themselves as patriots, gathered alongside a veteran military presence to guard the Cenotaph war memorial.

"Winston Churchill, he's one of our own," they chanted, near his statue.

Police commander, Bas Javid said a number of demonstrators had failed to disperse by 1600 GMT.

"There have been pockets of violence directed towards our officers. This is completely unacceptable and I condemn those involved," he added.

Police have also launched an investigation after a photo posted on social media appeared to show a man urinating on a memorial to Keith Palmer, the police officer killed in the 2017 terror attack outside parliament.

The Metropolitan Police would "gather all the evidence available to us and take appropriate action," said Javid.

London's mayor Sadiq Khan praised the force for doing a "fantastic job to control the situation."

"Millions of Londoners will have been disgusted by the shameful scenes of violence, desecration and racism displayed by the right-wing extremists who gathered in our city today," he added.

Britain has seen a wave of protests prompted by last month's death during a U.S. police arrest of George Floyd, an unarmed African-American, which triggered outrage around the world.

On Saturday, demonstrators in France met with the tear gas fired by the police while marching through central Paris chanting "No justice, no peace," and some climbed the statue of Marianne.

Meanwhile, across Australia thousands of protesters have rallied peacefully while wearing masks and the organizers were trying to keep the protesters spreading out. The biggest demonstration took place in the Western Australian capital, Perth, where several thousand people gathered in a park waving "Black Lives Matter" signs and Aboriginal flags.

Western Australia COVID-19 regulations prohibit crowds of more than 300 from gathering, although police weren't enforcing social distancing fines and organizers offered face masks and hand sanitizer to protesters on Saturday.

Police in the North Territory issued a statement saying the event was peaceful "and allowed community members to express their views in a safe environment."

(With input from agencies)