British police arrested 890 people on Saturday during a protest in London against the government’s decision to ban the activist group Palestine Action, the Metropolitan Police said Sunday. The force said 857 of those detained were arrested under the Terrorism Act for supporting a proscribed organization; 33 were held for other offences, including 17 for assaulting officers.

The arrests bring to nearly 1,600 the number of people detained in connection with demonstrations and acts of support for Palestine Action since the group was proscribed in July. The latest demonstration, organised by the campaign group Defend Our Juries, saw about 1,500 people sit outside Parliament holding signs that read “I oppose genocide, I support Palestine Action,” the organisers said. Police moved in within minutes and began detaining protesters, producing scuffles and angry exchanges as officers removed people from the crowd.

Deputy Assistant Commissioner Claire Smart said officers had faced assaults and abuse while policing the protest. “In carrying out their duties today, our officers have been punched, kicked, spat on and had objects thrown at them by protesters,” she said, calling the behaviour “intolerable.” Defend Our Juries dismissed claims of widespread protester violence, saying any aggression came from police officers and calling the assertions “frankly laughable.”

The tension follows months of escalating enforcement after the government proscribed Palestine Action in July, citing damage to national infrastructure and threats to security. The designation followed an incident in which activists broke into a Royal Air Force base and vandalised aircraft, spraying red paint into tanker engines and using crowbars, authorities said. The proscription makes it a crime to publicly support the organisation and carries a maximum penalty of 14 years in prison for membership or support.

Palestine Action formed in 2020 and has carried out direct actions targeting companies and sites it says are linked to the Israeli military, including facilities owned by Elbit Systems UK. Government officials have said the group’s actions have caused millions of pounds in damage and posed risks to national security. Then-Home Secretary Yvette Cooper said at the time that the assessments showed “this is not a nonviolent organisation.”

The group has challenged the ban in the High Court and won permission to contest the decision; the government is seeking to overturn that ruling. A hearing in the legal challenge is scheduled for Sept. 25.

International critics, including the U.N. human rights chief Volker Türk, have warned that the designation risks misapplying counterterrorism laws to conduct that is not terrorist in nature and could chill legitimate exercise of fundamental freedoms in the U.K. Türk said that under international standards, terrorist acts generally involve intent to cause death or serious injury or the taking of hostages.

Palestine Action’s co-founder Huda Ammori described the proscription as “catastrophic” for civil liberties. The group has attracted public support from cultural figures, including author Sally Rooney, who said she planned to direct proceeds to back the organisation’s actions.

The British government has emphasised that the proscription of Palestine Action does not target lawful campaigning or peaceful protest by other groups on either side of the Israel-Palestine debate. Separately on Saturday, police estimated about 20,000 people attended a large pro-Palestinian march in London.

Among those repeatedly arrested at demonstrations is Mike Higgins, 62, who is blind and uses a wheelchair. He said he had previously been arrested under the Terrorism Act and planned to return to protest despite the risk of further detention. “And I’m a terrorist? That’s the joke of it,” he said.

So far, more than 700 people were detained at earlier protests after the proscription, and 138 people have been charged under the Terrorism Act in connection with support for the organisation. London police said investigations are continuing and that officers will take action to prevent disruption and protect public safety while facilitating lawful protest where possible.