ABU DHABI—The Trump administration is putting a longstanding Russian demand at the heart of its latest push to end the war in Ukraine: renegotiating pan-European security in ways the Kremlin hopes will give it more influence in the region. Ahead of meetings in Abu Dhabi on Tuesday and Wednesday involving American, Russian, Ukrainian and European negotiators, U.S. officials said work on a ceasefire in Ukraine must proceed alongside discussions about Europe’s future security arrangements. The White House’s approach is causing alarm in many European governments, which believe Russia’s real goal is to rebuild a sphere of influence in Europe’s east,…