There were 890 people arrested at a demonstration against the ban on the group Palestine Action in London on Saturday, police say.
The majority of the arrests were for supporting a proscribed group under the Terrorism Act, while the Metropolitan Police said there were also a “significant” number of arrests made “after the protest turned violent”.
The number of arrests at the London demonstration has risen from the 425 announced on Saturday.
The government proscribed Palestine Action under anti-terrorism legislation in July, making membership of or support of the group a criminal offence, punishable by up to 14 years in prison.
The group was banned after activists broke into an RAF base and damaged two military aircraft earlier this year.
The Met said 857 arrests were for showing support for Palestine Action, while 33 were arrested for other offences, including 17 for assaults on police officers.
The protest saw hundreds of people gather in central London before writing messages in support of the proscribed group on placards at 13:00 BST. Officers began arresting people taking part shortly after.
The Met said most were taken to custody as they refused to provide their details or were found to have been on bail.
Deputy assistant commissioner Claire Smart said: “The violence we encountered during the operation was coordinated and carried out by a group of people, many wearing masks to conceal their identity, intent on creating as much disorder as possible.”
Defend Our Juries, which organised the rally, said officers had “violently assault[ed] peaceful protesters including the elderly, in order to try and arrest over a thousand people for holding cardboard signs”.
They said the demonstration showed the Palestine Action ban was “impossible to enforce and a preposterous waste of resources”.
The Met previously said the tactics used at the protest to “overwhelm the justice system… required significant resource which took officers out of neighbourhoods to the detriment of the Londoners who rely on them”.
Earlier this week, the Home Office was given permission to challenge a ruling which allowed Palestine Action to appeal against its ban under terrorism legislation.
The group’s co-founder, Huda Ammori, was granted permission to appeal in July after her lawyers argued the ban breached the right to free speech.
Former Home Secretary Yvette Cooper has previously defended the proscription by saying some supporters of Palestine Action “don’t know the full nature” of the group.
On Sunday, Defence Secretary John Healey told Sky News he expected her successor Shabana Mahmood would be “just as tough” on Palestine Action supporters.
