On July 12, police in the UK arrested dozens of activists at a protest event in support of a recently banned pro-Palestinian activist group.

The London Metropolitan Police Service issued a warning statement on July 11 about multiple events planned over the weekend by the banned group, Palestine Action. The police service noted that expressions of support for such groups constitute a criminal offense.

“Officers have made 41 arrests for showing support for a proscribed organisation,” the police service said in an updated statement on the afternoon of July 12.

The police service stated that officers arrested another individual for common assault.

On July 12, activist group Defend Our Juries claimed dozens more arrests in different communities across the UK—including Manchester, Cardiff, and Scotland—during other protest events in support of Palestine Action.

UK lawmakers approved legislation earlier in July designating Palestine Action as a proscribed terrorist organization. The designation came after members of the organization trespassed onto Royal Air Force base Brize Norton on June 20 and proceeded to vandalize a pair of military aircraft. Four members were taken into custody.

“The disgraceful attack on Brize Norton in the early hours of the morning on Friday 20 June is the latest in a long history of unacceptable criminal damage committed by Palestine Action,” UK Home Secretary Yvette Cooper said in the days after the vandalism incident on the military base. “The UK’s defence enterprise is vital to the nation’s national security and this Government will not tolerate those who put that security at risk.”

Palestine Action has been linked to multiple similar attempts to trespass and damage property owned by military contractors, including a facility in the UK operated by Israeli-owned company Elbit Systems.

Proscription places Palestine Action on a list alongside internationally designated terrorist groups, including Hamas and ISIS. Membership in such organizations can carry a penalty of up to 14 years in prison in the UK.

Critics of the move argue that Palestine Action is focused on civil disobedience and thus should not be listed alongside groups such as Hamas and ISIS.

“This is the first time in our history that a direct action civil disobedience group, which does not advocate for violence, has been sought to be proscribed as terrorists,” attorney Raza Husain told a court on July 4 as Palestine Action sought a court order halting the designation.

London’s High Court of Justice on July 4 ruled against Palestine Action’s attempt to halt the designation.

On July 5, the London Metropolitan Police Service arrested 29 other individuals during a protest event in support of Palestine Action.