Police in the UK have said a “pro-Hamas” leaflet was on sale at a protest in central London, where some demonstrators threw fireworks at officers and climbed on Trafalgar Square’s fountains on Saturday.
A copy of the pamphlet, which police said was “purported to support Hamas", is being reviewed by counter-terrorism officers.
The pro-Palestine protest came as police said they cut ties with the chairman of an official advisory body, after he was filmed leading a "from the river to the sea" chant.
The phrase is enshrined in Hamas’s 2017 constitution in Gaza, but dates back to the 1960s.
Police in London said lawyer Attiq Malik, chairman of the London Muslim Communities Forum, expressed views in the video, recorded filmed in 2021, which "do not align to the Met's values".
Mr Malik was in the police operations room during protests last month, the Sunday Telegraph reported.
Scotland Yard said the incident "highlighted past language and views expressed by Mr Malik that appear anti-Semitic and contrary with our values".
"As a result we will be immediately ceasing our relationship with Mr Malik while we investigate," police said.
Four officers were injured when fireworks were thrown during the pro-Palestine protest, after thousands gathered in Trafalgar Square. Six people were charged.
Protesters climbed on the square's famous fountains as the mostly peaceful group waved flags and banners.
At least one protester was carrying a banner that read "let's keep the world clean", with a picture of an Israeli flag being put in a bin.
Other protesters chanted "from the river to the sea, Palestine will be free", which Home Secretary Suella Braverman has called anti-Semitic. Pro-Palestinian protesters contest this definition of the slogan.
There were clashes between protesters and the 1,300 police officers on duty at the demonstration.
Five people were charged with failing to comply with conditions imposed under the Public Order Act and one was charged with failing to comply with a direction given under the Anti-social Behaviour, Crime and Policing Act, police said.
Pro-Palestinian protests in London - in pictures
One arrest was made on Sunday morning for a public order offence, after a man allegedly made anti-Semitic comments in Parliament Square.
Met Police official Karen Findlay said officers would be "sharper" in their response at future protests.
"We will take action on any placards being carried at protests which are inflammatory and incite racial hatred, or purport to be supporting a proscribed organisation," she said.
"These are offences and any such banners or material will be assessed by the Met's counter-terrorism command.
"As in recent weeks, we have been speaking to the organisers of the pro-Palestine march to discuss yesterday's demonstrations. We will continue to speak to them across this week as part of our ongoing planning for the weekend's Remembrance events and will monitor and review all information available to us."
UK Prime Minister Rishi Sunak and Ms Braverman have expressed concern about the prospect of further pro-Palestine protests on Saturday, when the country will mark Armistice Day.
Scotland Yard said it would use "all powers and tactics" at its disposal to prevent disruption to the occasion, including the banning of a procession when there is a risk of serious disorder.
"We fully appreciate the national significance of Armistice Day. Thousands of officers will be deployed in an extensive security operation and we will use all powers and tactics at our disposal to ensure that anyone intent on disrupting it will not succeed," Ms Findlay said.
The Festival of Remembrance at the Royal Albert Hall, which is usually attended by members of the royal family, will take place on Saturday, with a two-minute silence observed at 11am.
Remembrance Sunday events will take place at the Cenotaph in Westminster the following day.
The Palestine Solidarity Campaign pledged to avoid the area near the Cenotaph during a weekend protest.
Its planned route will take demonstrators from Hyde Park, about 1.6km from the Cenotaph, to the US embassy in Vauxhall, south of the Thames.
Ms Braverman has previously referred to pro-Palestine demonstrations as "hate marches".
The Cabinet minister said last week there was "an obvious risk of serious public disorder, violence and damage, as well as giving offence to millions of decent British people" if protests go ahead on Armistice Day.
"We recognise the terrible events in Israel and Gaza continue to have an impact on communities across London and recognise there is significant concern," Scotland Yard said on Sunday.
"Section 13 of the Public Order Act 1986 allows for the banning of a procession when there is a risk of serious disorder. It has to be approved by a Secretary of State.
"Sections 12 and 14 of the Public Order Act 1986 allow for conditions to be imposed to processions and public assembly to prevent serious disruption. We have used this legislation over recent weeks and will continue to use any legislation necessary to keep people safe."