Transcript for Deadly chemical attack in Syria kills dozens

Good evening. It's great to have you with us on a Tuesday night. We're going to begin tonight with the images that have stunned the world. It's hard to imagine that after six years of war in Syria, there could be something even worse than what many have already seen. Tonight, our team has taken great care to pour through the images, but we warn you, they're still difficult to see. A chemical attack, war planes dropping what appears to be a toxic gas. The white house responding. Here's Jonathan Karl. Reporter: Tonight, outrage over these scenes of horror and suffering in Syria. An apparent war crime, a suspected sarin gas attack by the government killing dozens and sickening many more, young children among the victims. Rescue workers desperately work to wash the chemical from the victims. Children clinging to life, struggling to breathe. The gas attacks are continuing every day and nobody is doing anything to stop this gas attack. Reporter: This attack following two chlorine attacks over the past week. While this local activist reported from one of those hospitals, it was it with another airstrike. The white house called the "Reprehensible" and said it "Cannot be ignored by the civilized world." But the statement also took aim at president Obama. "These heinous actions by the bashar al-assad regime are a consequence of the past administration's weakness and irresolution." That's a reference to president Obama's failure to punish Syria for crossing the so-called red line when it used chemical weapons in 2013. President Obama in fact boasted that he had worked out an agreement with Russia and Syria to get rid of Assad's chemical weapons. Assad gave up his chemical weapons. That's not speculation on our part. Reporter: Tragically, that was not true. At least some weapons remained. The big question right now is whether president trump will hold Assad accountable for using chemical weapons. He didn't talk about it today but he did say this in a speech on the economy. I'm not, and I don't want to be, the president of the world. I'm the president of the united States, and from now on, it's going to be America first. Reporter: Secretary of state Rex tillerson ignored questions on the attack. Mr. Secretary, any comment on the chemical attack in Syria? Bashar Al Assad should still be president of Syria? Reporter: But just last week tillerson signaled a significant change in longtime U.S. Policy that bashar al-assad must go. I think the status in the longer term status of president Assad will be decided by the Syrian people. Reporter: Tonight, these Syrian people aren't determining the status of Assad, they are trying to survive his brutality. And Jon with us live tonight from the white house. Secretary tillerson did not take questions on this today, but he appears to have taken to harsher line? Reporter: Yes, in a statement, condemning his ba barbarism. And called out Russia and Iran, saying they bear great responsibility for the attacks. But it's unclear what the trump administration will do about this. Thank you. We turn to the other major headline involving the white house, after president trump's claim that president Obama

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