Police have made three arrests during a fourth week of pro-Palestinian protests in central London.
One person was arrested after “displaying a placard that could incite hatred”, the Metropolitan Police said.
They were held under section 12 of the Terrorism Act.
Another was detained for assaulting a police officer while the third was arrested for breaching the Public Order Act.
All three were taken to a central London police station, Scotland Yard said.
Separately, British Transport Police said there was a sit-in protest at Charing Cross railway station and officers were in attendance.
“The protest has stopped some passengers from accessing the trains and platforms,” it said. “The station is currently working as exit-only for safety reasons.”
Earlier BTP said they were aware of “footage circulating on social media showing chanting on a tube train”.
Ahead of the protests, Britain’s chief rabbi warned of “hateful extremism”.
Sir Ephraim Mirvis said the lines between demonstrators and “those who support the brutal terrorism of Hamas” had become “badly blurred”.
With a protest being held in Trafalgar Square on Saturday afternoon, the Metropolitan Police said there would be a “sharper focus” on using social media and face recognition to root out criminal behaviour.
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Meanwhile, Prime Minister Rishi Sunak has argued the staging of pro-Palestinian demonstrations on Armistice Day would be “provocative and disrespectful”.
It follows reports tens of thousands of demonstrators are planning to take to the streets on 11 November to call for an immediate ceasefire, although organisers have promised to avoid Whitehall where the Cenotaph war memorial is located.
Sir Ephraim says the deadly attack carried out by Hamas in Israel on 7 October, triggering the latest bloody conflict in Gaza, mean many of the chants heard during recent protests, including calls for “jihad” and an “intifada”, should be viewed as supporting the militants.
Writing in The Times, he said: “The world feels different because at the very moment when it should be clearer than ever what is meant by Hamas’s ‘resistance’, ‘jihad’, ‘uprising’, or ‘intifada’, more and more people are now openly calling for these things in cities across Britain and the world. This is hateful extremism.
“We must have the moral courage to call it by its name and to face it down.”
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Sir Ephraim pointed to a Manchester protest with a banner showing support for “Palestinian resistance” and said there was no ambiguity in the words used.
He wrote: “Did every person who attended that march truly wish to associate themselves with acts of such barbarity? I sincerely hope that they did not.
“Nevertheless, it could not be clearer that, at the very least, the lines between those who wish only to advocate for the welfare of innocent Palestinians and those who support the brutal terrorism of Hamas have become badly blurred.
“Those lines have remained blurred in the subsequent demonstrations, in which a minority have proudly displayed their extremism on their banners and in their chants, while the majority stand alongside them.”
Sir Ephraim added: “Similar lines have become blurred in the sermons being given in a minority of mosques, inciting hatred and even violence against Jews, while the majority of prominent Muslim clerics are silent.
“They are blurred on university campuses where a minority of students and lecturers are declaring their support for ‘intifada’ while the majority appear indifferent.
“It is imperative that we redraw these lines of moral clarity without delay.”