WASHINGTON — Momentous arguments inside the West Wing over the future of the Paris climate accord became a messy public spectacle on Wednesday, with some aides saying that President Trump had decided to abandon the landmark global warming agreement while others insisted that no decision had been made.

Three administration officials with direct knowledge of the intense White House debate said early Wednesday morning that Mr. Trump was expected to withdraw the United States from the 2015 climate change accord that committed nearly every nation to take action to curb the warming of the planet.

In addition, three other officials said later Wednesday that they expected him to withdraw from the agreement, though they said that decision could still change. Hours later, Mr. Trump said on Twitter that he had made his decision and would announce it in the Rose…