Thunberg, 22, joined a protest Tuesday morning that opposed the treatment of people being held in prisons before trials relating to Palestine Action activities.

Greta Thunberg was arrested in central London on Tuesday while supporting pro-Palestinian activists who are staging a hunger strike to protest their imprisonment while awaiting trial on charges relate...

Footage released here by activist group Prisoners for Palestine shows police removing a sign from Thunberg that reads “I support Palestine Action prisoners” and “I oppose genocide.”