British police arrested Swedish ⁠activist Greta Thunberg in London on Tuesday at an anti-Israel protest, U.K.-based campaign group Defend Our Juries said.

Thunberg was arrested under the Terrorism Act for holding a sign that said she supported prisoners linked to ⁠Palestine Action, an organization which the British government has proscribed as a terrorist group, ​Defend Our Juries said.

A City of London spokesperson said two people had been arrested for throwing red paint on a building.

"A ⁠little while later, a 22-year-old woman also attended the scene," the police spokesperson said in statement. "She has been arrested for displaying ⁠an item (in this ​case a ⁠placard) in support of a proscribed organization (in this case Palestine Action) contrary to Section 13 of the Terrorism Act 2000."

Defend Our Juries said it targeted the building because it was used ⁠by ​an insurance firm which they said provided services to the British arm of Israeli defense firm Elbit Systems.