British police arrested Swedish climate activist Greta Thunberg in London on Tuesday during a pro-Palestinian demonstration, according to UK campaign group Defend Our Juries.

The group said Thunberg was detained under the Terrorism Act after displaying a placard expressing support for prisoners linked to Palestine Action, an organisation that has been proscribed as a terrorist group by the British government.

A spokesperson for the City of London Police confirmed that officers had made arrests at the scene. Two people were initially detained on suspicion of throwing red paint on a building.

“A little while later, a 22-year-old woman also attended the scene,” the spokesperson said in a statement. “She has been arrested for displaying an item — in this case a placard — in support of a proscribed organisation, contrary to Section 13 of the Terrorism Act 2000.”

Defend Our Juries said the protest targeted the building because it is used by an insurance company that the group claims provides services to the British subsidiary of Israeli defence firm Elbit Systems. Photo by Stefan Müller (climate stuff) from Germany, Wikimedia commons.