The head of the Environmental Protection Agency (EPA) has said it will be up to other countries to negotiate a new climate deal with the US, after Donald Trump announced he was pulling America out of the Paris Accord.

Scott Pruitt also said human activity did contribute to global warming, amid speculation about Mr Trump's views on the subject.

It came as the President's aides refused to say if he believes in climate change, having once called it a "hoax".

When asked about the joint statement issued by France, Italy, and Germany stating the Paris accord was not open to being renegotiated, Mr Pruitt did not seem concerned.

Speaking during a news conference at the White House, the EPA chief was bullish, telling reporters a seat at the negotiating table was a given because “we’re the United States”, adding: “We have nothing to be apologetic about."

He repeated Mr Trump’s rhetoric on putting “America first” and suggested that it was in every other country's interest to talk to the US about a restructured Paris accord “or a new deal”.

Mr Pruitt cited figures on carbon emissions reduction for the 2000 to 2014 period, spanning the previous Obama administration, but noted that the US did this through "innovation and technology, not government mandate".

He said that if former President Barack Obama’s administration wanted the Paris accord to be “enforceable, they should have ratified it as a treaty".

Mr Obama had the US ‘join’ the agreement by way of an executive order instead of going through Congress for a formal treaty ratification because the administration felt climate deniers would block it. Mr Pruitt himself said he was not convinced anything could be done about the impact of human activity on climate change.

That process is what gave Mr Trump the authority to withdraw from the deal, but the US will still need to go through a formal four-year withdrawal process as outlined in the agreement text.

Mr Pruitt said the Trump administration has been discussing next steps with the Department of Justice.

He also maintained Mr Trump’s false narrative that the agreement “did not hold China and India accountable”, arguing that the agreement needs to be renegotiated because it “puts America at an economic disadvantage".

Christina Hioureas, chair of the United Nations Practice Group at law firm Foley Hoag LLP in New York, told The Independent that although “there may be other avenues under international law to hold accountable non-compliant States”, thinking that the US economy could be hurt by implementing targets in the Paris accord is "miscalculated".

The Paris Agreement sets different standards for developed and developing countries and Mr Trump’s requirement that “burdens [of carbon emissions reductions]...[are] equally shared by countries all around the world“ shows an apparent lack of understanding of the purpose of the deal.

It was formulated to account for the historical climate damage done by wealthy countries to poorer countries and provisions to help developing countries grow their economies without over-reliance on the same fossil fuel method used by those wealthy countries.

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France, Italy, and Germany have said they ”will step up efforts to support developing countries, in particular the poorest and most vulnerable, in achieving their mitigation and adaptation goals".

Helping smaller economy countries in Africa, Latin America, and Asia grow through through a cleaner energy mix will reduce emissions and limit global warming while pushing richer countries to curb their own emissions.

China signed a bliateral deal with the US under the Obama administration – ahead of the Paris signing – and estimated they would need until 2030 to reach a ”peak“ of carbon emissions – mostly through inexpensive coal burning – in order to build up their economy to a point where they can afford to start transitioning to more renewable sources of energy.

China will then begin to reduce carbon emissions and increase the proportion of renewable sources of energy. They are already a leader in solar panel production.

Mr Pruitt said the US would continue to “export clean coal...innovation and technology” and “teach them” about how to run their energy sector.

“On a broader economic scale, withdrawal and non-compliance and scaling back of subsidies may result in a missed opportunity for the US to lead the charge,” on renewable energy technology, said Ms Hioureas.

Several states and cities all over the US have already voiced opposition to the Trump administration.

The bipartisan US Conference of Mayors (USCM) said in a statement that “mayors have vowed their continued commitment to reduce greenhouse gas emissions to alleviate the impacts of global warming despite what happens at the national level".

Republican governors of Vermont and Massachusetts have also expressed their commitment to improving and protecting the environment.

When White House Press Secretary Sean Spicer was asked about this, he said the administration “believes in states rights” and recognises that state and local officials will do what they feel will serve their citizens best.

He also said the President thinks renegotiating the Paris accord or a new deal is “in the best interest of the country” without providing specifics on why Mr Trump would not just change emissions reductions targets, cut funding to global climate funding schemes, or simply not be party to any global pact.

The White House did not respond to a request for comment on the matter.

”There's no legal reason why it couldn't be amended, but I don't think it needs to be amended or 'renegotiated' in order to address the concerns raised by the President," Sue Biniaz, former US State Department Deputy Legal Adviser on climate, told The Independent.

Todd Stern, the Special Envoy on Climate Change during the Obama administration, said it was ”extremely hard to imagine any country wanting to renegotiate [the agreement] because they felt the US got a bum deal".