Environmental campaigners have targeted Shell petrol stations over the company's plans to drill for oil in the Arctic.
The protesters have used an emergency shut-off switch to stop petrol going to the pumps and have removed a fuse to delay it being switched on again.
The first station targeted was the Shell garage in Edinburgh's Dalry Road, where they attempted to scale the roof.
Shell is due to begin drilling at two offshore sites in the Alaskan Arctic in the coming weeks.
Greenpeace's Sara Ayech said: "The oil giant Shell is preparing, for the first time, to unleash a drilling fleet of huge vessels upon the fragile and beautiful Arctic, home of the polar bears.
"An oil spill in the Arctic would be catastrophic for wildlife, such as walruses and whales, and Shell knows full well that it would be impossible to clean up after such devastation. The Arctic must be saved, and made a global sanctuary where oil drilling is banned."
A spokesman for Shell said: "Shell recognises that certain organisations are opposed to our exploration programme Offshore Alaska, and we respect the right of individuals and organisations to engage in a free and frank exchange of views about our operations.
"Recognising the right of individuals to express their point of view, we only ask that they do so with their safety and the safety of others, including the general public and Shell personnel, in mind."