Britain said on Monday it would use anti-terrorism laws to ban the campaign organization Palestine Action, making it a criminal offense to belong to the group after its activists damaged two UK military planes in protest at London’s support for Israel.

The proscription would put the pro-Palestinian group on a par with Hamas, al-Qaeda or ISIS under British law, making it illegal for anyone to promote it or be a member. Those who breached the ban could face up to 14 years in jail.

Members of the group clashed violently with police officers during a protest in London’s Trafalgar Square on Monday, after it was forced to relocate its planned protest outside the British Parliament, staged amid reports that the ban was set to be announced.

Palestine Action has regularly targeted British sites connected to Israeli defense firm Elbit Systems as well as other companies in Britain linked to Israel since the start of the conflict in Gaza in 2023.

In its latest and most high-profile action, two of its members entered a Royal Air Force base in central England on Friday, spraying paint into the engines of the Voyager transport aircraft and further damaging them with crowbars.

“The disgraceful attack on Brize Norton… is the latest in a long history of unacceptable criminal damage committed by Palestine Action,” Home Secretary Yvette Cooper said in a written statement to parliament. “The UK’s defense enterprise is vital to the nation’s national security and this government will not tolerate those that put that security at risk.”

She said the group’s actions had become more aggressive and caused millions of pounds of damage.

Under British law, the Home Secretary can ban a group if it is believed it commits, encourages or “is otherwise concerned in terrorism.” The banning order will be laid before parliament on June 30 and will come into effect if approved.

Palestine Action, which says Britain is an “active participant” in the conflict in Gaza because of military support it provides to Israel, called the ban “an unhinged reaction” that it would challenge, and accused Cooper of making a series of “categorically false claims.”

“The real crime here is not red paint being sprayed on these war planes, but the war crimes that have been enabled with those planes because of the UK government’s complicity in Israel’s genocide,” it said in a statement.

Earlier on Monday, the group was forced to change the location of a planned protest after police banned it from staging a demonstration outside parliament, otherwise a popular location for protests in support of a range of causes.

The group said in response that it changed the location of its protest to Trafalgar Square, which lies just outside a police exclusion zone.

Gathering in Trafalgar Square, members of the group and its supporters clashed violently with police officers who sought to shut down the protest after the ban was announced.

Protesters surged toward police when officers tried to detain someone, while onlookers chanted “let them go.” In a statement, London’s Metropolitan Police said Monday afternoon that they shut down the protest at 3 p.m. but that “crowds remained in the road.”

“Officers moved in to give final warnings and a number of people who refused to leave were arrested,” the police statement added. “The road is now clear.”

Earlier, police said three other protesters had been arrested, two for obstruction and one for “a racially aggravated public order offense.”

The police said late on Sunday that it would impose an exclusion zone for a protest planned by the group outside the Houses of Parliament.

“The right to protest is essential and we will always defend it, but actions in support of such a group go beyond what most would see as legitimate protest,” Met Police Commissioner Mark Rowley said at the time.

Palestine Action’s members are alleged to have caused millions of pounds of criminal damage, assaulted a police officer with a sledgehammer and, in the incident last week, damaged two military aircraft, Rowley added.

In recent months, the group has sprayed the London offices of Allianz Insurance with red paint over its alleged links to Israeli defense company Elbit, and vandalized US President Donald Trump’s Turnberry golf course in Scotland.

Times of Israel staff contributed to this report.