While Trump emerged from the summit without a final decision on the Paris pact, he declared in a tweet Saturday that he will make a final decision next week.
London [U.K.], May 27: The G 7 leaders, in their final communique, have said that the summit in Italy has failed to bridge differences over climate change after United States President Donald Trump remained non-committal over the Paris Agreement.
"The whole discussion about climate has been hard, or rather very unsatisfactory", Merkel said after the summit.
He returns to Washington now to find the USA capital much the same as he left it - engulfed in the latest revelations about the federal investigation into his campaign's contacts with Russian Federation and with questions about the future of his presidency still swirling.
"'To the families who endure time apart or constant time apart, your sacrifices do not go unnoticed", Trump said.
Meanwhile, Democrats are urging Trump not to withdraw from the agreement.
US Defence Secretary James Mattis, in comments to be aired fully in a TV interview today, said Trump - famously skeptical of global warming - is now "wide open" on the issue.
Host Paolo Gentiloni, the prime minister of Italy, said the group was also inching closer to finding common language on trade, a contentious issue between Trump - elected on an "America First" platform - and the six other leaders.More news: Iraqi forces launch operation to seize last Islamic State enclave in Mosul
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Speaking broadly speaking about Trump's foreign trip, Cohn said the "the president was able to make some of the most fantastic deals that have been made by an administration ever". Almost 200 countries had pledged support to reduce carbon emissions in the landmark global warming deal.
The White House had hoped to use Trump's five-stop trip as a moment to reset. But he also held one-on-one meetings with the leaders of Japan, the United Kingdom, Canada and Germany. China, which along with the United States produces 44 per cent of the world's carbon dioxide, agreed to talks with Obama that led to the 2015 Paris Agreement.
US officials said he had enjoyed "robust" conversations with his allies in Sicily and had also learnt a lot - especially in the debate on climate change, which he has previously dismissed as a hoax.
Trump's first venture overseas as president also revealed that he is still very much finding his footing on the world stage. Trump tweeted that he will make his decision next week, signaling that he has yet to officially make up his mind.
And Trump took a new swipe at Germany, reportedly telling other European leaders that the country's trade practices were "bad", an account that has been confirmed and denied by administration officials.
They were also disappointed that he did not touch on Russian Federation, which was expelled from what was then called the G8 in 2014 because of its annexation of Crimea from Ukraine.
Trump is set to engage in discussions about the global economy and climate.
The U.S. president is due to return to Washington later on Saturday at the end of a nine-day tour of the Middle East and Europe - his first foreign trip since taking office.
The trip has largely gone off without a major misstep, with the administration touting the president's efforts to birth a new coalition to fight terrorism, while admonishing partners in an old alliance to pay their fair share.