Transcript for Civilians killed, children struggling to breathe in alleged chemical attack in Syria
about to see are disturbing. Here's Ian Pannell. Reporter: The dchaos and carnage of Syria's war, spilling into doumahe rebel-held district near the Syrian capital Dama. The area has been bombard for months,dreds of innocents killed. But wch what haened two daysag haunti images. Fficult to watch. But he world has largely ignored their suffering so far. Perhaps this ry W a red line crossed. And no longessible to ignore. An alleged chemicaack that left children pouring into a make shift clinic, eyes bug, some foaming at the mouth. Manytruggling sy T stay alive, some failing too. The last twodays were the worstays that I watched and D . Reporter:ammed sanas one of the medical STA tending the victims. The situation was too cause of the high numbe of injured and the F number of medical am. Reporter: Entire family appear to have been killed in the ak. Rebelctivists and rescueray rhaps 40 or more are dead, suffer kating from an unknown since. R W, the claimsimpole to verify, but some are asking whether the syrianovernment has once again attacked own people with chemical weapons -- a war crime. It was an atrocious . It was horrible. Reporter: President tru conddhe alleged attack Toda vowing to mate, major decisions how to proceed over the next 24 to 48 hours We are very concerned. When a thing like that can happen, this is about humy. We'r talking about humanity, and can't be allowed to en. I think the one thing that makes this differ for this president ihose images. When H sees something like that, he reacts to that. I think that makes a difference. Reporter: Ais INT, the U.S. Hasn'tonfirmed a chemical agent was used. But a state department source tellbc N the victims' mptoms are cont with an asphyxiati agent and a nerve agent of some type. We are beyondwing pictures of dead ba. We are beyond appeals to conscience. Reporter: U.N. Ambasr I Haley and eight other countriesay in tense, emergenc.n. Meeting, directly targeting Syria's president br Al Assad and promising U.S. Retaliation. The monster who is responsible for theseacks has no consce. Not even to be shocked by pictures O dead children. Orter: But there are no sy steps here. Efforts storm what's happening in the war-torn country are all the harder by the interference of foreign powers. Russia still backs Assad, warning military intervention can lea the most serious consequences. Russia would losedibility with T Syrians if the were to engage any attack and fail T do so. Ich means T a potential for a s./russia confrontation. Reporter:r the weekend, president trump tweeted, bla Russian president Putin and Iran for backing Syrian ident Assad. Does putinr responsibility for this? He may he may. And if H does it's going to be tough. Very tough. E'll pay a price if -- Everybody's going to pay a he will, everybody will. There have four str in douma alone since the begin of January. What's different this , we have more people killed and with the video aftermath of those children suffering. Reporter: Russia's U.N. Representative today Calle the attack fake news, claiming was staged and that ran specialists who went the area tookl samples. Tlator: Not a single L resident confirmed the chemic attack hg taken place. So a local hosp, there were noorbout sptoms from atoxic substance.just chlorine. Reporter: This vidha by a local activist showed what appear to be Russian agents assessing the purported attack site, leang without taking Sas. But only independentitors can assess if amical attack has happened, and that S days or weeks. Not the brief T the Russ spent on site. E suspect chemical attack is latest in a conflict lasting years that's killed 400, and cimated entire CI, prompting an exodu of over 5.5 million. Assad is king his own people, and how he does it is not as import a the fact that he continues T kill hundreds of thousands of the sypeople. Reporter: Back in 2012, president Obama said that use of ccal weapons against civilians would cross aed line and bring enormous consequences Syria's president. Aed Lin for us is, we start seeing a bf chemical weapons moving around or being utilized. That would change mycaus. That would change my tion. Reporter: But Assad escalated attacks on hiswn people. As theebels responded with force, America largely stood on theelines. Tiust over a year wn images emerged of a chemical attack in the northwesternow E more than 80 peowere ki. That crosses many red lines. Reporter: Within days, president trump ordered air kes on a syrianirfield that was used launch that chemical Ta. When he dropped those tomahawk missiles last ye it was seen so big a so alarmin and 59 tomk missiles. The truth is, thatas a pretty small str they were able to flying off that airfield I think it was da. Reporter: Nearly two weeks agsident trumpxpressed a Desi to G U.S. Troops out of Syria. Ry mission terms of that was getting R of isi we've almost completed that task and we'll be making the decision quickly in coordination with others in Thea. Reporter: But it's the Syrian re, not ISIS, that's killed ndreds ofhousands of people in this war and launched nearly half a doz ccal attacks over the past year,ording to the U.N. Obviously what we did last year hasot deterred Assad hetinues to kill his own people witical weapons Reporter: While the world condemns thesible use of chemical ons, it's the almost daily barragef bombs from cntional warfare that's taken the biggest toll since fig broke out between Assad's army and R groups seven Y ago. I saw theorrors of the civil war early ,Hile reporting for the bbc. This hospi in aleppo was overwhelmed every day bti and casualties. The siton inside her is one of unbelievable chaos. We've J been here for very F time, and every few minutes, newients are brought in, as the doctors work under fire to try and keep them alive. Reporter: Eventually it was flattened by reg planes. The rebels too accused of crimes, but it's the regime that's charge with killing on an industrial scale. The challenge, how to respond. Thiss not necessarily a precursor toore.s. Presence or mily action in syria.but it does complicate the extraction pro if the president does want to continue Dr from Syria. Repr: Tonight a fire of sorts in the town where the alleged cca attack happened. Bel fighters and theirfamilies living in a convoy of ses. But this isn'tver. The fighters, the families, the children will move elsewhere, an there will be more days like ese. Ter years non-stop pain and death, America and the world must now decide what the willing do and what erce till really make. "Nightlin" I'm ianannell in LN. ???
This transcript has been automatically generated and may not be 100% accurate.