Ban Ki-moon arrives in Seoul for Nuclear Security Summit Ban Ki-moon, secretary-general of the UN, arrives at the Incheon International Ai...

Ban Ki-moon arrives in Seoul for Nuclear Security Summit

Ban Ki-moon, secretary-general of the UN, arrives at the Incheon International Airport in the city of Incheon, South Korea, on March 24, 2012. BAN Ki-moon arrived in Seoul, capital of South Korea, on Saturday to attend the Nuclear Security Summit. (Xinhua/Park Jin hee)

Police stand guard outside the COEX (Convention and Exhibition) Center in Seoul, South Korea, on March 24, 2012. Seoul beefed up security prior to the 2012 Seoul Nuclear Security Summit slated to be held in COEX from March 26 to 27. (Xinhua/Yao Qilin)

Police cars park outside the COEX (Convention and Exhibition) Center in Seoul, South Korea, on March 24, 2012. Seoul beefed up security prior to the 2012 Seoul Nuclear Security Summit slated to be held in COEX from March 26 to 27. (Xinhua/Yao Qilin)

Ban Ki-moon (1st L), secretary-general of the UN, arrives at the Incheon International Airport in the city of Incheon, South Korea, on March 24, 2012. BAN Ki-moon arrived in Seoul, capital of South Korea, on Saturday to attend the Nuclear Security Summit. (Xinhua/Park Jin hee)

BAN Ki-moon arrived in Seoul, capital of South Korea, on Saturday to attend the Nuclear Security Summit.