WASHINGTON - US President Donald Trump does believe the world climate is changing and humans bear some responsibility, US Ambassador to the United Nations Nikki Haley said in an interview on Saturday.

Amid furious worldwide criticism of Trump's decision on Thursday to quit the Paris climate agreement, White House spokesmen had refused on Friday to say whether the president even believed the climate was changing. He said frequently during last year's election campaign that climate change was a hoax.

But Haley, in an interview with CNN aired on Sunday, did not hedge.

"President Trump believes the climate is changing and he believes pollutants are part of the equation," she said.

He "knows that it's changing and that the US has to be responsible for it and that's what we're going to do," she said.

Haley said the terms of the international agreement curbing global emissions - signed by every country but Nicaragua and Syria - were "too onerous" and placed US companies at a disadvantage.

Trump's decision has left the United States virtually isolated on the world stage, and his insistence that he will seek to "renegotiate" the international accord has done little to ease a wave of bitter condemnation.

Against that backdrop, a string of administration officials went on the offensive on Friday to justify the Republican president's decision to abandon the 195-nation Paris deal.

Trump's top climate adviser Scott Pruitt was indignant: "The world applauded when we joined Paris. And you know why? I think they applauded because they knew it would put this country at a disadvantage."

Trump himself ignored a question about climate change when asked by journalists during an unrelated event on Friday, although he did joke that Thursday's decision had proven "controversial".

White House press secretary Sean Spicer also refused to answer repeated questions on the subject.

Agence France-presse