President Donald Trump said on Wednesday that the United States could "conceivably" return to the Paris climate accord, although he stopped short of signalling any move in that direction.

"Frankly, it's an agreement that I have no problem with, but I had a problem with the agreement that they signed, because, as usual, they made a bad deal," Trump told a news conference.

"So we can conceivably go back in," added the president, who pulled out of the 2015 accord on curbing global warming emissions last June.