US soldiers wear chemical warfare gear during a joint military exercise with South Korea at a US Army base in Dongducheon, 40kms north of Seoul, on March 3, 2011 aimed to simulate the detection and disposal of North Korea's chemical, biological, radiological and nuclear weapons.  US and South Korean soldiers displayed their techniques for handling weapons of mass destruction (WMD) in the face of North Korea's nuclear sabre-rattling. AFP