President Donald Trump held the door open to a reversal of his decision to pull the United States out of the Paris climate accord on Thursday, but did not say what he would need in return to persuade him to do so.

Trump, who has made few friends in Europe with his rejection of the 2015 Paris agreement and his "America First" trade stance, met with French President Emmanuel Macron as both leaders sought common ground to reset an awkward relationship.

"Something could happen with respect to the Paris accords, let's see what happens," Trump told a news conference. "If it happens, that will be wonderful, and if it doesn't, that'll be OK too."