German Chancellor Olaf Scholz said for the first time that his government could postpone the planned closure of its remaining nuclear reactors, as he criticized a decision by Russia to constrain gas flows to Germany—a move that could deal a severe blow to Europe’s largest economy. Last month, Russia shut down for maintenance its giant Nord Stream pipeline, which connects Russia and Germany under the Baltic Sea and is operated by Russian state-owned energy producer Gazprom PJSC.