"Another attack in London by a loser terrorist", Trump added.
Trump on Friday also used the London train attack to renew calls for his controversial travel ban on travelers from several predominantly Muslim countries, which is the subject of fierce legal battles in the United States but has partially gone into effect.
He also tied his demand for a more robust travel ban to an unusual claim that Scotland Yard was familiar with Friday's bombers ahead of time and missed the chance to catch them before he launched the attack.
The London bombing happened on the underground train during the morning rush hour.
"The threat of terrorism that we face is severe, but by working together we will defeat them". After a back-and-forth between their administrations, Khan said the Trump's planned official state visit to the United Kingdom should be canceled. "Any speculation is unhelpful". London Mayor Sadiq Khan said Londoners will see more police on the streets of the British capital after an explosion at a metro station, which officers said was a "terrorist incident".
"I think he means generally that this kind of activity is what we're trying to prevent", McMaster said. "It just keeps going and going", and suggested that the US may not be tough enough on terror.
Trump's top national security aide said that Trump was simply noting British law enforcement is keeping an eye on terrorist groups seeking to carry out attacks on its soil.
In a prerecorded statement, Prime Minister Theresa May condemned the "cowardly" attack "intended to cause significant harm".
Trump responded on Twitter: "At least 7 dead and 48 wounded in terror attack and Mayor of London says there is 'no reason to be alarmed!'".
The Trump administration's original policy called for a 90-day travel ban - which will be over in late September - and a 120-day refugee ban which will expire a month later.
With each half-baked tweet that comes out of his phone, Donald Trump chips away at the credibility of the presidency as an institution.
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