On Twitter, Trump wrote, "You have to be kidding me?!: Terror attacks are part of living in a big city, says London Mayor Sadiq Khan." Accompanying the tweet was a link to a September story by The Independent, which reprinted a quote from Khan in The Evening Standard, in which he said the threat of attacks is "part and parcel of living in a big city."
"It is a reality, I'm afraid, that London, New York, other major cities around the world have got to be prepared for these sorts of things," Khan said at the time.
In the interview, Khan criticized Trump's father, then–presidential candidate Donald Trump Sr., for saying within minutes of the explosion that it was time to "get tough."
"I'm not going to speculate as to who is responsible or how the police in New York should react," Khan told The Evening Standard. "Speculating when you don't know the facts is unwise."
Four people were killed and at least 40 more were injured in the attack. The suspect was also killed, shot by police on the scene.