Extinction Rebellion activists climbed on to trains at Stratford, Canning Town and Shadwell in Thursday's rush hour. Eight protesters have been arrested, British Transport Police (BTP) said.
The Jubilee Line and Docklands Light Railway were temporarily suspended. Extinction Rebellion later said it would "take stock" of the reaction to the latest action for future protests. Spokesman Howard Rees said: "Was it the right thing to do? I am not sure. "I think we will have to have a period of reflection. It is too early to say."