Donald Trump Jr. is ready to throw off the mockery that recently came with dressing up in a flannel shirt and sitting awkwardly on a tree-stump for a New York Times photographer.

With victims of Wednesday’s terror attack in Westminster, London, variously dead, dying, and gravely injured, Trump Jr. goaded the mayor of the British capital via Twitter.

“You have to be kidding me?!” he wrote about two hours after a man ran a car into pedestrians and then fatally stabbed a police officer. “Terror attacks are part of living in big city, says London Mayor Sadiq Khan.”

Trump Jr. was selectively quoting part of an earlier interview, reported by the Independent, Khan gave after a bomb explosion in New York’s Chelsea neighborhood last September injured 31 people.

Then, Khan had told Pippa Crerar of the London Evening Standard that the injured in New York were in his thoughts and prayers.

He said he was not going to speculate as to who was responsible for the explosion and other devices found, or opine on how the police in New York should react.

In full, Khan then said, “Part and parcel of living in a great global city is that you have got to be prepared for these things. You’ve got to be vigilant. You’ve got to support the police who do an incredibly hard job. You’ve got to support the security services, and I think speculating when don’t know the facts is unwise.”

Lest anyone reading Trump Jr.’s parsing of Khan’s actual words think London’s mayor did not take the likelihood of a terror attack on the capital seriously, Khan has previously talked about the possibility of attacks in extremely grave terms.

When he was elected, Khan said, “Nothing is more important to me than keeping Londoners safe. I want to be reassured that every single agency and individual involved in protecting our city has the resources and expertise they need to respond in the event that London is attacked.

“The terrorists are evolving their tactics and we have got to evolve our response to them all the time. I am afraid the consequences of a terror attack are very, very scary. They want to kill. They want to maim and terrify. It is my job to try to make sure that we are as safe as we can be.”

Condemnation of Trump Jr. by angry Britons came days after the U.S. was forced to apologize to the U.K. after White House press secretary Sean Spicer repeated a false assertion that British security services had helped wiretap Donald Trump.

M.P. Wes Streeting called Trump Jr.’s words “a disgrace.”

Other wondered if Trump Jr. had read the article he had linked to.

In an email to the New York Times, Trump Jr. wrote: “I’m not going to comment on every tweet I send.”

When Khan was asked about the social-media post on CNN, he was dismissive. “I’m not going to respond to a tweet from Donald Trump Jr.—I’ve been doing more important things over the past 24 hours,” he said.