PARIS/BERLIN, April 14 (Reuters) - More than three years after Russia's invasion of Ukraine, Europe's energy security is fragile. U.S. liquefied natural gas helped to plug the Russian supply gap in Europe during the 2022-2023 energy crisis.

But now that President Donald Trump has rocked relationships with Europe established after World War Two, and turned to energy as a bargaining chip in trade negotiations, businesses are wary that reliance on the United States has become another vulnerability.

Against this backdrop, executives at major EU firms have begun to say what would have been unthinkable a year ago: that importing some Russian gas, including from Russian state giant Gazprom (GAZP.MM) could be a good idea.

That would require another major policy shift given that Russia’s invasion of Ukraine in 2022 made the European Union pledge to end Russian energy imports by 2027.