Donald Trump is expected to withdraw the US from a landmark global climate agreement, a White House official has said, although aides are looking for "caveats in the language" related to the exit and the decision is not yet final.
Abandoning the Paris deal would fulfil a central campaign pledge for the president, but would anger international allies who spent years in difficult negotiations that produced an accord to reduce carbon emissions.
Mr Trump faced considerable pressure to hold to the deal during meetings with European leaders and Pope Francis on his recent trip abroad. The official said the president and his staff were finalising the details of a pullout.
"I will be announcing my decision on the Paris Accord over the next few days. MAKE AMERICA GREAT AGAIN!" Mr Trump tweeted on Wednesday.
While he currently favours an exit, he has been known to change his thinking on major decisions and tends to seek counsel from a range of inside and outside advisers, many with differing agendas, until the last minute.
His senior aides have been divided on the accord.
Mr Trump is meeting secretary of state Rex Tillerson, who has favoured remaining in the deal, while chief strategist Steve Bannon supports an exit, and senior adviser Jared Kushner generally thinks the deal is bad, but would like to find a way to see if the US emissions targets can be changed.
Ivanka Trump's preference was to stay, but she made it a priority to establish a review process so her father heard from all sides of the debate, said a senior administration official.
Nearly 200 nations, including the US under Barack Obama, agreed in 2015 to voluntarily reduce their greenhouse gas emissions in an effort to combat climate change. Withdrawing would leave the US aligned only with Russia among the world's industrialised economies in rejecting action to combat climate change.
A senior European Union official said the EU and China would reaffirm their commitment to the pact regardless of what Mr Trump does, and spell out, during talks on Friday in Brussels, how they would meet their obligations.
Mr Trump pledged during his presidential campaign to withdraw the US from the pact immediately after taking office, but has wavered since winning the election.
During his overseas trip last week, European leaders pressed him to keep the US in the pact. French President Emmanuel Macron spoke with him at length about the issue during a meeting in Brussels, and at the Vatican, Cardinal Secretary of State Pietro Parolin made his own pro-Paris pitch to Mr Trump and his advisers.
News of Mr Trump's expected decision drew swift reaction from the United Nations. The organisation'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."
House Democratic leader Nancy Pelosi referred to it as "a stunning abdication of American leadership and a grave threat to our planet's future".
She said the agreement "honours our collective moral responsibility to leave future generations with a planet that is clean, healthy and sustainable".
Mr Trump claimed before taking office that climate change was a "hoax" created by the Chinese to hurt the US economy.