US President Barack Obama will visit South Korea on April 25th, diplomatic sources here have said. The sources in Washington said Obama will travel to Seoul after a stop in Japan, according to Korea's (KBS WORLD) website. The upcoming visit would be Obama's fourth to South Korea since he took office in 2009. During his two-day stay, Obama will hold a summit with South Korea's President Park Geun-hye and reaffirm their countries' alliance. He is also likely to discuss ways to accelerate the denuclearization of the Korean Peninsula and the South Korea-U.S. free trade agreement. Japanese daily the Nihon Keizai Shimbun said Obama's trip to Japan will run from April 23rd to the 25th. It said Obama was planning to stay two days in Japan but decided to extend his trip by one day at Japan's request. After wrapping up his trip to South Korea, Obama will visit Malaysia and the Philippines.