Transcript for British Prime Minister speaks out about London terror attack

I did mention president trump's tweet. Here's what he sent this morning. Another attack in London by a loser terrorist. These are sick and demented people in the sites of Scotland yard. Must be proactive. The tweet suggesting the suspects were in the sights of authorities in London. What did the prime minister of Britain think of that tweet? George Stephanopoulos asked her that today. The prime minister scheduled was upended by this attack today. I spoke with her right after she emerged from an emergency meeting with her counter terror team. I know you've just met with your counter terror team. What's the latest on what happened today? Yes. Well, we've had another terrorist attack in London on the London underground. Cowardly attack. And it was a device that was obviously intended to cause significant harm. Treating it as an act of terror right now. And president trump was up and tweeting this morning. He said that those behind this were in the sights of Scotland yard. Is that true? Well, I don't think it's helpful for anyone to speculate on what is an ongoing investigation. The police and the security services are doing the work necessary to discover the full circumstances of this cowardly attack that's taken place, and to identify all those who are responsible. As you can see the prime minister not very thrilled with the president's tweet this morning, but right after our interview she did speak with president trump. He put in a call and he offered support for Britain right now in the wake of the terrorist attack and sources here say they will continue to have a constructive relationship. David? Thank you. Getting reaction from Britain's prime minister tonight. And George will have much more with prime minister may Sunday on "This week" with George. Tough talk from the white house.

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