organs and can lead to death by suffocation. germany chancellor told putin directly do not use chemical weapons in ukraine. as the battle came to a stalemate after one month it is a possibility inside the russian playbook. something that they have used successfully in the past in syria. >> it has the effect positive for assad and russian-backed forces because it allowed the syrian military to regain the initiative. if there is one thing that russia does not have right now in ukraine is the initiative. >> what is not clear at this point is how nato would respond to a chemical weapons attack inside ukraine. would a cloud of poisonous gas that drifts over nato territory be considered an attack? >> dana: a really good question. we're one month into this war and you recently returned from ukraine. can you tell us what it was like covering the war on the