TODAY | April 26, 2013
>>> we're learning more about the civil war waging in syria . how will the obama administration respond to intelligence reports that chemical weapons have been used? richardeningle is nbc's chief foreign correspondent. this was the so-called red line .
>> the uk has called this a war crime . now the world is watching to see if this will be enough to convince washington to change course. after more than two years and 70,000 dead, the white house strongly suggested bashar al ass assad's regime has used chemical weapons against syrian rebels but did it with so many caveats as to make a u.s. military response highly unlikely. defense secretary hagel repeated a message the white house delivered to members of congress.
>> in talking to our intelligence people in the last couple of hours they have a reasonable amount of confidence that some amount of chemical weapons was used.
>> reporter: u.s. intelligence officials believe traces of the nerve agent sarin were found in blood samples taken from victims of an attack last month near aleppo. president obama has warned syria using chemical weapons would be a game changer.
>> a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized. that would change my calculus.
>> i think it's pretty obvious that red line has been crossed.
>> reporter: white house officials say they still have too many questions about the origin of the weapons and how they were used and want a u.n. investigation. but syria so far hasn't been cooperating with other inspectors or u.n. teams and syrian rebels say bashar al assad will take inaction from washington as approval. qatar, which funds and arms the rebels a gre s agrees.
>> no reaction, he will escalate.
>> reporter: france, britain and israel have all accused the syrian government of using small amounts of chemical weapons but this time, unlike during the run-up to the iraq war , washington is stressing the need for caution. the syrian opposition, to be clear, doesn't want u.s. troops on the ground. instead they want access to more weapons, want a no fly zone but to achieve that would likely require sustained bombings from the air by nato and the u.s.
>> richard engel , thanks.