The prime minister expressed her frustration as she spoke for the first time about the “cowardly attack” at Parsons Green underground station in west London, which injured at least 22 people.
Trump claimed on Twitter that the terrorist attack involved “sick and demented people who were in the sights of Scotland Yard”, despite no such information having been released publicly by police. He also blamed it on “loser terrorists”, promoted his travel ban and advocated a “proactive and nasty” policy against Islamic State.
Asked about Trump’s potential breach of convention on intelligence sharing, May was unusually critical of the US president, saying: “I never think it’s helpful for anybody to speculate on what is an ongoing investigation.”
When the president tweeted, no suspect had been identified and no group or individual had claimed responsibility for the blast.
The Met police said the president’s comments regarding Friday morning’s incident were unhelpful and “pure speculation”.
There was no immediate response from the White House to questions about the basis of Trump’s assertion.
Speaking outside the White House on Friday, Trump made no reference to her rebuke. “It’s a terrible thing,” he said. “It just keeps going and going, and we have to be very smart, we have to be very, very tough. Perhaps we are not nearly tough enough.
“It’s just an absolutely terrible thing. In fact, I’m going to call the prime minister right now. We have to be tougher and we have to be smarter.”
Downing Street said Trump offered May his condolences over the attack during a telephone call later on Friday.
In a summary of the call, a White House statement said: “President Trump spoke with Prime Minister Theresa May to convey his sympathies and prayers for those injured in the terrorist attack today in London. The President pledged to continue close collaboration with the United Kingdom to stop attacks worldwide targeting innocent civilians and to combat extremism.”
Trump makes no reference to May’s rebuke when asked about London train explosion
In the aftermath of the Manchester Arena bombing in May, British police temporarily suspended intelligence sharing with the US, after a series of leaks to US media.
The broadcaster CBS disclosed the name of the bomber, Salman Abedi, citing US sources, at a time when British authorities were asking the media to withhold the information to protect the investigation. The New York Times then published detailed photographs of the bomb scene that had been taken by British investigators.
Nick Timothy, a newspaper columnist who was formerly May’s chief of staff, wrote on Twitter of Trump’s remarks: “True or not – and I’m sure he doesn’t know – this is so unhelpful from the leader of our ally and intelligence partner.”
Eighteen people were taken to hospital after the explosion, which was being treated as an isolated incident, and four people made their own way to hospital. London ambulance service said: “None are thought to be in a serious or life-threatening condition.”
Trump’s intervention had echoes of his tweets after the London Bridge attack in June, when he criticised Sadiq Khan’s call for calm.
In a statement, the London mayor confirmed that the Parsons Green explosion was being treated as terrorism and said: “I urge all Londoners to be calm and vigilant.”
At a morning press briefing, the Met assistant commissioner Mark Rowley said: “We now assess that this was a detonation of an improvised explosive device. As you will have seen, there are reports of 18 injuries. I understand most of those to be flash burns.”
Rowley said the investigation was being led by the Met counter-terrorism command, supported by MI5. Police officers would be deployed across the capital’s transport network, he added.
At around the time Rowley spoke, Trump sent consecutive tweets:
Another attack in London by a loser terrorist.These are sick and demented people who were in the sights of Scotland Yard. Must be proactive!
“The travel ban into the United States should be far larger, tougher and more specific – but stupidly, that would not be politically correct!”
Trump’s travel ban against refugees and others from six majority-Muslim countries is in force but not in full effect, as court challenges on constitutional grounds continue. A first version, against seven countries, was withdrawn after similar challenges.
“We have made more progress in the last nine months against Isis than the Obama Administration has made in 8 years,” he said. “Must be proactive & nasty!”
The UK foreign secretary, Boris Johnson, will be able to ask Trump to be more cautious with his comments in future when he sees him on Monday at a special UN general assembly session on reforming the organisation.
May and Johnson have repeatedly urged politicians and the media not to speculate about the identity of a terrorist, or whether any suspects were under surveillance by UK security services.
Overall, the Foreign Office has become more relaxed about Trump’s plain speaking, but the security services that work under its political direction will be infuriated by any sign that the US president has leaked intelligence information.
Trust and confidentiality between UK and US intelligence is the bedrock of the relationship between the two services. May is is due to make prevention of extremism on the internet one of her three key themes at the UN next week. Although May does not support Trump’s talk of cutting off the internet, she agrees with him that technology giants have not done enough to tackle online extremism.
