The administration of US President Donald Trump has taken the big step of officially notifying the United Nations of its decision to pull out of the 2015 Paris climate accord, after Trump announced in June that the deal "punished" the US.

"Today, the United States submitted a communication to the United Nations in its capacity as depositary for the Paris Agreement regarding the US intent to withdraw from the Paris Agreement as soon as it is eligible to do so," the State Department said in a statement on Friday (4 August).

Nonetheless, Washington has pledged to continue to participate in talks during the exit process, leaving the door open to re-engage on the deal if the terms improved for the US, it added.

"The United States will continue to participate in international climate change negotiations and meetings... to protect US interests and ensure all future policy options remain open to the administration," the department said.

Although the US on Friday gave its decision in writing for the first time, under the Paris climate change deal, countries that sign up for the deal will have to wait for three years from the date it comes into legal effect before they can initiate the process to quit.

This means the US cannot officially withdraw until 4 November, 2019.

And the actual process of leaving will take another year, which means it would not be complete until the US goes to polls to elect its next president in 2020. But if Trump does not win a second term and the country gets a new president, he or she can decide to rejoin the agreement, the BBC noted.

As a result, the notification is seen as a largely symbolic statement with no legal weight.

"The United States supports a balanced approach to climate policy that lowers emissions while promoting economic growth and ensuring energy security," the department said in the release.

In a speech in June, Trump announced withdrawal from the Paris deal, saying being part of it would cost millions of American jobs, and hindered the oil, gas, coal and manufacturing industries. But he had also said he would begin negotiations to re-join the accord to create an entirely new one to ensure it is all favourable to US businesses.

His decision drew widespread criticism from environmentalists to politicians across the world, including North Korean leader Kim Jong-un. Pyongyang said the withdrawal demonstrates the US' "height of egoism and moral vacuum".

Donald Trump vows to exit Paris climate agreement
Donald Trump vowed to pull out of the Paris climate agreement in June RTV

"As the president indicated in his June 1 announcement and subsequently, he is open to re-engaging in the Paris agreement if the United States can identify terms that are more favourable to it, its businesses, its workers, its people, and its taxpayers," the State Department said in the statement.

The climate accord was adopted by nearly 200 countries in Paris during the COP21 climate conference in December 2015. It aims to reduce greenhouse gas emissions to limit global temperature rise to well below 2C.

The deal requires the countries to set national targets for reducing their greenhouse gas emissions.

The nations ratifying the pact are expected have to update their targets once every five years and must report on their progress.

The US pledged to be part of the Paris deal under former president Barack Obama and reduce greenhouse gas emissions by as much as 28%.