cover up in syria the use of chemical weapons. it hasn't done that so far. but it is part of what these people worry this is not beyond the realm of possibility. railroad what weapons does moscow have? no one knows exactly. there is no evidence that russia has used more common chemical weapons like chlorine and sarin. all are banned internationally for their cruelty. >> russia would pay a severe price if they use chemical weapons. >> that price is not yet clear, though. how do you think the world would react? >> it would be crossing a line but it is not necessarily one that will spark military response. if -- if putin knows that we will react militarily, then we know that he can decide when and on what terms the west enters this war or nato enters this war, which would be incredibly unwise. >> reporter: at a u.n. security council meeting on friday, the u.s. was in no mood for disinformation.