The United States is the world's biggest carbon emitter after China.
Although the officials caution no decision is final until the president officially announces it, the White House is now working on how to roll out the announcement and explain the reasons behind Trump's decision.
He said Wednesday that he will make an official decision on the matter over the next few days. He promised to "cancel" the Paris deal during the election campaign previous year, warning that it was "bad for USA business" because it allowed "foreign bureaucrats control over how much energy we use".
"In walking away from this agreement, the President is denying scientific truths, removing safeguards that protect our health and our environment, protecting polluters and their dirty energy agenda, and threatening our national and global security", she said.
President Donald Trump is expected to withdraw the United States from a landmark global climate agreement, a White House official said Wednesday, though Trump and aides were looking for "caveats in the language" related to the exit and had not made a final decision.
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. The organization's main Twitter page quoted Secretary-General Antonio Guterres as saying, "Climate change is undeniable".
In a jibe at the USA administration, Juncker told the audience at an event of the Confederation of German Employers in Berlin that "not everything that is written in global agreements is fake news".
Pelosi added that she believes withdrawing from the pact will have economical ramifications for the US: "Rejecting the pact also sends a strong message to the marketplace to direct innovative, entrepreneurial investments in the clean energy economy elsewhere". "Climate solutions provide opportunities that are unmatchable".More news: Chechnya's leader invites Macron, Merkel to visit his region
Alternatively, the president could pursue a faster course by dropping out of an underlying treaty, the United Nations Framework Convention on Climate Change.
Michael Brune says future generations will look with "stunned dismay at how a world leader could be so divorced from reality and morality".
Guterres said in that speech that "it would be very important for the US not to leave the Paris agreement".
A White House official says President Donald Trump is expected to withdraw the United States from the Paris climate accord.
The European Union and China, meanwhile, will reaffirm their commitment to the Paris climate change accord this week regardless of whether the US pulls out of the pact, a senior EU official said.
The official insisted on anonymity in order to discuss the decision before the official announcement.
Democrats had been calling on Trump to stay in the agreement, with Senate Minority Leader Chuck Schumer announcing last week that 40 Democratic senators had sent the President a letter urging him to honor the United States commitment.