Russia won’t immediately resume exports of natural gas to Europe through its Nord Stream 1 pipeline, worsening a shortage that threatens to tip the continent into an energy crisis this winter. On Friday, Russian state energy giant Gazprom said it would not resume flows through the pipeline on Saturday as planned because it had detected an oil leak at its Portovaya compressor station. The pipeline has been shut since Wednesday for maintenance. It didn’t give a timeline of when exports might resume.