Description:South Korea's conservative activists rallied against North Korea on Wednesday (February 13) after Pyongyang's third nuclear test a day earlier. About 150 protesters gathered in downtown Seoul for the rally, burning North Korean national flags and photos of Kim Jong-un, young leader of the communist state. Pyongyang said on Tuesday (February 12) that the test was an act of self-defence against "U.S. hostility" and threatened stronger steps if necessary.(0:47)