The US refused on Monday to sign on to a Group of Seven pledge that calls the Paris climate accord the "irreversible" global tool to address climate change.
The G-7 environment ministers issued a final communique on Monday after their two-day meeting, the first since the US announced it was withdrawing from the Paris climate pact.
In a footnote to the communique, the US said it wouldn't join with the other six countries in reaffirming their Paris commitments, but said it was taking action on its own to reduce its carbon footprint.
"The United States will continue to engage with key international partners in a manner that is consistent with our domestic priorities, preserving both a strong economy and a healthy environment," the footnote read.
As a result, the US said it would not join those sections of the communique on climate and multilateral development banks.
The head of the US Environmental Protection Agency, Scott Pruitt, had attended the first few hours of the summit on Sunday, but then left to attend a Cabinet meeting in Washington.
Presenting the communique on Monday, Italy's environment minister, Gian Luca Galletti, called the Paris accord "irreversible, non-negotiable and the only instrument possible to combat climate change."
He said the other G-7 countries hoped to continue "constructive dialogue" with the US, but insisted on the Paris parameters.
"Everything else for us is excluded," he said.
The 2015 Paris agreement aims to prevent the Earth from heating up by any more than 2 degrees Celsius (3.6 degrees Fahrenheit) since the start of the industrial age.
President Donald Trump announced the US was withdrawing from the Paris accord earlier this month, framing it as a "reassertion of America's sovereignty."
He has said the US could try to re-enter the deal under more favourable terms, but the EU — and in particular Italy, France and Germany — have said the Paris accord cannot be renegotiated.