U.S. President Donald Trump has long ranted against wind energy — claiming turbines are unsightly, dangerous to wildlife and too expensive — with him threatening to upend decades of industry progress just a few hours after returning to power.

"We're not going to do the wind thing," Trump said Monday as he returned to the Oval Office for the first time in four years as commander-in-chief.

"Big, ugly windmills," he said as he signed a series of executive orders that has brought the sector into crisis, adding that "they kill your birds, and they ruin your beautiful landscape."