Leaders of the G7 group of rich nations have failed to agree a statement on climate change, reports BBC News.
Six world leaders reaffirmed their commitment to the Paris accord, the world's first comprehensive deal aimed at reducing greenhouse emissions.
However, the US has refused to recommit to the agreement, saying it will make a decision next week.
Mr Trump, who once dismissed global warming as a "hoax", has previously threatened to pull out of the accord.
This is Mr Trump's first G7 summit - during his first foreign trip.
G7 leaders from the US, Britain, Canada, France, Germany, Italy and Japan have agreed a statement on fighting terrorism.
The final communique issued at the G7 summit in Italy said the US "is in the process of reviewing its policies on climate change and on the Paris Agreement and thus is not in a position to join the consensus on these topics".
However, the other G7 leaders pledged to "reaffirm their strong commitment to swiftly implement the Paris Agreement".
German Chancellor Angela Merkel said the discussion on climate change had been "very unsatisfactory", adding "we have a situation of six against one".
Mr Trump tweeted: "I will make my final decision on the Paris Accord next week!"
His economic adviser, Gary Cohn, said Mr Trump "came here to learn. He came here to get smart. His views are evolving... exactly as they should be."