BERLIN - The main natural gas pipeline between Russia and Germany shut down for scheduled maintenance Monday, raising concerns that Moscow could use the repairs as a pretext for a longer shutdown as it wields energy supplies as leverage in the Ukraine war.European ministers warned that it was unclear whether Moscow would turn the taps on the Nord Stream 1 pipeline back on after the 10 days of scheduled work. Germany's economy minister, Robert Habeck, said Berlin was concerned about a "nightmare scenario" this winter if Russia decides against doing so."Everything is possible, everything can happen," he told Deutschlandfunk radio...