An American businessman, Stephen Lynch, who previously worked closely with Rosneft, Russia's state oil company, is aiming to buy a Swiss company that controls Russia's controversial Nord Stream 2 natural gas pipeline, according to U.S. Treasury and other documents obtained by The Washington Post.

Lynch's proposal could pave the way to reactivating the pipeline, which links Russia and Germany if a cease-fire is reached in the ongoing war in Ukraine. This move comes as Europe braces for Pr...