U.S. President Donald Trump has described the explosion on a London tube train as another attack "by a loser terrorist".
In a series of tweets in response to the suspected terrorist attack, he also claimed the police in the capital may have missed an opportunity to prevent it and suggested the government "cut off" internet access to extremist groups.
"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!" Trump tweeted in the aftermath of the blast at Parsons Green station.
It's not clear whether Trump's statement was the result of information he had been given by his aides. He later added: "Loser terrorists must be dealt with in a much tougher manner. The internet is their main recruitment tool which we must cut off & use better!"
Trump also used the explosion to promote his travel ban and continued: "The travel ban into the United States should be far larger, tougher and more specific – but stupidly, that would not be politically correct!"
His comments were quickly condemned as "unhelpful". Nick Timothy, Theresa May's former chief wrote on Twitter: "True or not – and I'm sure he doesn't know – this is so unhelpful from leader of our ally and intelligence partner."
In an interview with the BBC, the Prime Minister echoed Timothy's views. "I never think it's helpful for anybody to speculate on what is an ongoing investigation," she said.
A police spokesperson told CNN that Trump's comment is "pure speculation given we don't know who is involved. Any speculation is unhelpful."
Asked about Trump's tweet, Mayor of London Sadiq Khan added that he hadn't seen it. "I haven't had a chance to look at Twitter, let alone tweet," Khan said.
Police say 22 people were wounded in the explosion, mostly with burns, when an improvised explosive device exploded on the train in south west London. Emergency workers say none of the injuries is believed to be life-threatening.
The Metropolitan Police say they "are making fast-time inquiries to establish who was responsible and are working closely with the security services."
Additional reporting from Associated Press.