He also urged Germans to step down from the supervisory boards of Russian companies, specifically mentioning former Chancellor Gerhard Schroeder, who sits on the board of Russia's Rosneft.
"We must act more strongly against Putin's supporters," he said in the interview, published on Tuesday. "Oligarchs who send their children to English private schools, have villas on the Cote d'Azur and go shopping on the Kurfuerstendamm. Capital streams have to be tracked and drained."
Changes to the precise timetable from Germany's already agreed exit from nuclear power should not be a taboo, he said, adding that it could also be worth revisiting a pledge in the government's coalition agreement to stop drilling for gas in the North Sea.
(Reporting by Thomas Escritt; Editing by Sarah Marsh)
