Norwegian environmental youth group Nature and Youth staged a protest yesterday on top of the roof of opposition Labour Party's central office in Oslo, saying they wanted an end to plans for gas-based power in Norway. NTB new agency reported the group, a unit of Friends of the Earth, decorated the building to look like a giant gas-based power plant by mounting a pipe adorned with the Labour logo and spewing smoke. The action was a protest against the view of Labour, the biggest party with 65 seats of the 165-member parliament, on building gas power plants in Norway.