NATO has activated its defences against chemical and nuclear weapons as concerns mount that Russia might use such weapons in Ukraine, Secretary General Jens Stoltenberg said Thursday as Western leaders met to further punish Russia for the invasion now in its second month. Speaking after an extraordinary NATO summit in Brussels that coincided with G7 and European Council summits, Stoltenberg said the 30 leaders of the defence alliance had agreed to send Ukraine “detection, protection, and medical supplies, as well as training for decontamination and crisis management.” “So we are taking measure…