Germany could find itself in a no-win situation if Russia invades Ukraine, pitting Berlin's main gas supplier against its most important security allies.

Chancellor Olaf Scholz would face pressure from the United States and other Western allies to respond to any invasion by stopping the recently completed Nord Stream 2 pipeline from Russia to Germany going into operation.

But doing so would risk exacerbating a gas supply crunch in Europe that has been widely blamed on a dearth of gas flows from Russia, and has caused energy prices in Europe to soar.