Transcript for G-20 summit protests erupt in violence

Good evening, and it's great to have you with us here on a Thursday night, and we begin with president trump in Germany tonight amid those violent protests in chaos in the streets. Protesters in Hamburg clarning with police if riot gear as the g20 summit begins. They are fighting against globalism. We have seen it before, but this is the first time with president trump who is now there for crucial meetings. The officers firing water cannons on the crowd. ABC's senior white house correspondent, Cecilia Vega, witnessing it herself, and she leads us off tonight. Reporter: Police and protesters taking over the streets of Hamburg tonight. A sea of marchers pushing up against police lines. The faceoff leading to violent clashes just as world leaders arrived in town. And this is what president trump will see when he arrives on the streets of Hamburg, police in the streets, here in armored cars, protestors all over. Some throws bottles at German police in riot gear. Officers trying to disperse the crowds. Tackling people to the ground, kicking others. Finally turning water cannons on them. The streets covered in a cloud of tear gas. So far, police say at least 59 officers injured. The marchers protesting globalization and capitalism, many of them in black masks. But also in the crowd, images of America's leader. The g20 summit underway just about two miles from the clashes. President trump meeting with Germany's Angela Merkel, the two leaders chatting and shaking hands. A warmer encounter than their first awkward meeting in the oval office just a few months ago. Thank you. Br Reporter: Early early in the day in Poland, a very different scene. Take a look at this, both sides of the street here in Warsaw completely packed full of people waiting to catch a glimpse of president trump. President trump supporters showing up in droves. Donald Trump! Donald Trump! Reporter: In the heart of Warsaw, at the sight of Poland's uprising against the Nazis, the president delivering an ominous warning, presenting a clash of civilizations between the west and what he called "Radical islamic terrorism." The fundamental question of our time is whether the west has the will to survive. Do we have the confidence in our values to defend them at any cost? Do we have enough respect for our citizens to protect our borders? Do we have the desire and the courage to preserve our civilization in the face of those who would subvert and destroy it? Reporter: But tonight in Hamburg, protesters delivering a message of their own to the leaders of the world's most powerful countries, you're not welcome here. And Cecilia Vega with us tonight from Germany, and let's get back to the pictures. The president has likely been briefed on the scope of these protes protests, but where do stand, and do they expect more tomorrow? Reporter: Police here tell us they are bracing for heavy and violent protesting throughout this summit. David, in fact, they are describing heavy rioting taking place here in Hamburg. They say the protesters have been trying to get to that summit site. Just a couple of miles away from where we are, and they are trying to prevent prevent that from happening. In the meantime, you were there today, and the president saying his strongest words yet, saying, we urge Russia to cease it activities to Ukraine, but Cecilia, when he was asked about Russian meddling in our election on the eve of his big meeting with Putin, does he believe it was the Russians? Here's what he said. Well, I think it was Russia, and I think it could have been other people and other countries. It could have been a lot of people interfered. I have said it very simply. I think it very could well have been Russia, and it could well have been other countries and I won't be specific, but I think a lot of people interfere. I think it has been happening for a long time. So the president said there it could be Russia or others. Do we know if the president will bring this up in this meeting and who will be in that room? Reporter: We're told he is not expected to press Putin at all on this issue of the meddling in the election. Secretary of state Rex tillerson will be in there, and sergey lavrov, and it's a small circle. Cecilia, thank you. In the meantime, president trump is dealing with yet another threat tonight, and this

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