South Korea said on Wednesday world leaders visiting Seoul for a nuclear summit next week will discuss North Korea and Iran's “illegitimate” atomic activities, angering the North that said such talk would be a “declaration of war”. Foreign Minister Kim Sung-hwan told Reuters that while nuclear weapons and proliferation issues were not on the formal agenda at the Nuclear Security Summit in Seoul from Monday, Iran and North Korea would clearly be key issues on the sidelines. “There is no question that international community has serious concerns about the illegitimate nuclear activities of North Korea and Iran,” he said in a written interview. Along with South Korean host President Lee Myung-bak, leaders from four other six-party states — US President Barack Obama, China's Hu Jintao, Russia's Dmitry Medvedev and Japan's Yoshihiko Noda — will be in Seoul for the two-day summit. North Korea's announcement of a long-range rocket launch in April is now expected to take centre stage.