British officials directly reproached Donald Trump for his response to a bombing on a London Underground platform that left 29 people hospitalized on Friday. “Loser terrorists must be dealt with in a much tougher manner,” Trump tweeted on Friday. “The internet is their main recruitment tool which we must cut off & use better!” In another tweet, he speculated that the person or persons responsible for the attack “are sick and demented people who were in the sights of Scotland Yard,” seemingly faulting London’s Metropolitan Police Service for not stopping suspects he suggested were already on their radar. Trump then offered his condolences to British Prime Minister Theresa May in a phone call, during which she reportedly complainedabout his insensitive reaction. “I never think it’s helpful for anybody to speculate about what is an ongoing investigation,” May said in a television interview afterward. “As I’ve just said, the police and security services are working to discover the full circumstances of this cowardly attack and to identify all those responsible.”

Other British officials also directly condemned the U.S. president for his comments. “True or not - and I’m sure he doesn’t know - this is so unhelpful from leader of our ally and intelligence partner,” May’s former Chief of Staff Nick Timothy tweeted. London Mayor Sadiq Khan, who Trump previously criticized after a terror attack that left seven dead, said he had been too busy with police and emergency services to look at Trump’s Twitter account.

The backlash is hardly the president’s first transatlantic row. In Trump’s second month in office, the White House ignited a minor diplomatic scandal when Sean Spicer baselessly accused the British government of colluding with the Obama administration to wiretap Trump Tower. British officials also stopped sharing intelligence with the U.S. briefly earlier this year, amid concerns that U.S. intelligence officials would continue to leak images from an attack in Manchester to the American media. “I will make clear to President Trump that intelligence that is shared between our law-enforcement agencies must remain secure,” May said at the time. British Home Secretary Amber Rudd said the leaks were “irritating.” (At a meeting in NATO later that month, Trump condemned the leak and added that he’d ask the Justice Department to review it.)

Hours after Friday’s attack, the White House released a statement pledging “to continue close collaboration with the United Kingdom to stop attacks worldwide targeting innocent civilians and to combat extremism.” Officials say Chief of Staff John Kelly, who has been tasked with the unenviable responsibility of reining in Trump’s Twitter impulses, was not with Trump when he tweeted about “loser terrorists” on Friday morning.