London Mayor Sadiq Khan renewed his rivalry with Donald Trump, mocking the U.S. president for “dealing with a hurricane out on the golf course” over the weekend.

Khan's comments came after Trump pulled out of a trip to Poland to commemorate the 80th anniversary of the start of World War II to concentrate on Hurricane Dorian, but then played golf at his private club in Virginia.

“He’s clearly busy dealing with a hurricane out on the golf course,” Khan, who traveled to Poland to attend a commemoration ceremony on Sunday, told POLITICO's London Playbook.

Khan also took aim at the U.S. president for emboldening racists to speak out from the fringes of society.

“These people have been inspired by mainstream politicians who subscribe to their point of view,” Khan said. Trump “is a guy who amplifies racist tweets; amplifies the tweets of fascists; says things that are deeply objectionable. If I don’t stand up and call that out I think I’m doing a disservice to Londoners who chose me as their mayor.”

Khan and Trump have traded barbs since 2016, when the then-U.S. presidential candidate floated the idea of banning Muslims from traveling to America, and Khan, London's first Muslim mayor, called Trump's views on his religion "ignorant." More recently, Trump called Khan a "stone cold loser" on Twitter, and the London mayor fired back, saying the U.S. president's missives were worthy of "an 11-year-old."