Donald Trump is going to withdraw from the Paris climate agreement, according to sources close to the president, who spoke on condition of anonymity.

Trump tweeted on Wednesday morning (31 May): "I will be announcing my decision on the Paris Accord over the next few days. MAKE AMERICA GREAT AGAIN!"

The agreement was signed by Barack Obama in October 2016. A total of 195 nations signed up to the deal. So far just Nicaragua and Syria have declined.

News of Trump's expected decision drew swift reaction from the United Nations. The organization's main Twitter page quoted Secretary-General Antonio Guterres as saying, "Climate change is undeniable. Climate change is unstoppable. Climate solutions provide opportunities that are unmatchable."

The Sierra Club's executive director, Michael Brune, called the expected move a "historic mistake which our grandchildren will look back on with stunned dismay at how a world leader could be so divorced from reality and morality."

Trump pledged during his presidential campaign to withdraw the US from the pact immediately after taking office, but had wavered on the issue since winning the election.

Trump claimed before taking office that climate change was a "hoax" created by the Chinese to hurt the US economy. Such an assertion stands in defiance of broad scientific consensus.

Trump's top aides were divided on the issue; some advocated withdrawal, others urged him to stay. One potential compromise that had been discussed involved remaining in, but adjusting the US emissions targets.

Senior Republicans have been urging the president to leave the accord for some time. Last week senate majority leader Mitch McConnell called for a "clean break."

22 Republicans sent Trump a letter last week urging him to follow through on his campaign pledge to pull out of the climate accord. Most of the senators who signed are from states that depend on the continued burning of coal, oil and gas.

There have been influential voices urging Trump not to ditch the Paris accord. Forty Democratic senators sent Trump a letter urging him to stay in, saying a withdrawal would hurt America's credibility and influence on the world stage.

Hundreds of high-profile businesses have spoken out in favor of the deal, including Apple, Google and Walmart. Even fossil fuel companies such as Exxon Mobil, BP and Shell say the United States should abide by the deal.

The US is the world's second largest emitter of carbon, following only China. Beijing, however, has reaffirmed its commitment to meeting its targets under the Paris accord, recently canceling construction of about 100 coal-fired power plants and investing billions in massive wind and solar projects.

A departure from the agreement would break up the legacy left behind by Obama, who had worked hard on climate change in his eight years in office.

A decision on how to exit is yet to be taken, with a formal withdrawal taking up to three years. A more extreme exit could take place at a faster rate.

While at the G7 summit in Sicily last week, world leaders including Angela Merkel and Emmanuel Macron had urged Trump to remain inside the agreement.

Donald Trump
Trump has bee critical of the agreement for some time Mandel Ngan/AFP/Getty Images