UN Secretary General Antonio Guterres has expressed disappointment over President Donald Trump's decision to pull out of the Paris Accord, saying he is confident all other parties to the ambitious pact will continue with their efforts to reduce the emissions.

"The decision by the United States to withdraw from the Paris Agreement on climate change is a major disappointment for global efforts to reduce greenhouse gas emissions and promote international security," according to a statement read by Guterres's spokesperson Stephane Dujarric to reporters here on Friday.

Guterres's response came as Trump made the expected announcement from the White House's Rose Garden that the US will withdraw from the Paris Climate Agreement, adopted after years of international negotiations in December 2015 by the 196 parties to the UN Framework Convention on Climate Change (UNFCCC).

"The Secretary-General remains confident that all other parties to the Paris agreement will continue to demonstrate vision and leadership, along with very many cities, states and businesses in the United States and around the world by working for the low-carbon, resilient economic growth that will create quality jobs and markets for 21st century economic prosperity," the statement by the UN Chief said.

Trump will however stick to the withdrawal process laid out in the Paris agreement, which in effect means that the US will be able to fully exit the pact only by November 2020, leaving a final decision up to the American voters in the next presidential election.

When asked how long it will take for the US government to pull out of the agreement according to the established protocols, Dujarric said he will not comment at this point on any legal issues. On the caveat that Trump is ready to renegotiate the agreement, Dujarric said that is a question for the parties which negotiated the agreement.

The Paris Agreement's central aim is to strengthen the global response to the threat of climate change by keeping the global temperature rise in this century well below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit it to 1.5 degrees Celsius.

The landmark agreement, which entered into force last November, calls on countries to combat climate change and to accelerate and intensify the actions and investments needed for a sustainable low carbon future, and to adapt to the increasing impacts of climate change.

Guterres said in the statement that the Paris Agreement was adopted by all the world's nations because they recognise the "immense harm" that climate change is already causing and the enormous opportunity that climate action presents.

Guterres stressed that it is "crucial" the United States remains a "leader" on environmental issues and he "looks forward to engaging with the American government and all actors in the United States and around the world to build the sustainable future on which our grandchildren depend." 

The UN Chief underscored that the Paris Climate agreement offers a meaningful yet flexible framework for action by all countries and the transformation envisaged in the deal is already underway.

The Paris Agreement was a defining moment in the legacies of both former UN Secretary General Ban Ki-moon as well as Trump's predecessor Barack Obama. India had ratified the Paris Agreement on climate change on October 2 last year on the birth anniversary of Mahatma Gandhi, given the Indian leader's philosophy and strategy of non-violence.

US Ambassador to the UN, Nikki Haley said by deciding to withdraw from the climate agreement, Trump acted in America's best interest, "moving away from a flawed agreement that placed too heavy a burden on American jobs, and opening the door to a new agreement that reaches the right balance.

"As a Governor, I always worked to balance economic growth and environmental protection. We can, and we must do both," she said adding that America will remain a leader in environmental protection.

"However the Trump administration will not jeopardise our economy in order to please other countries that doesn't come anywhere near our environmental standards," she said.