Obama heads to South Korea for nuclear summit South Korea is preparing to host a high-profile nuclear security summit U.S. President Barack Obama will be among more than 50 heads of state at the meeting He will visit the demilitarized zone between South and North Korea for the first time Sunday North Korea's nuclear ambitions are not on the agenda, but are likely to be discussed on the sidelines Seoul, South Korea (CNN) -- President Barack Obama travels to South Korea Saturday on a three-day trip centered on an international nuclear security summit in Seoul. He is due to arrive in Seoul early Sunday, where he will hold a bilateral meeting with his South Korean counterpart Lee Myung-bak. Top officials from 54 countries, including China and Russia, will attend the summit meeting on Monday and Tuesday. But its message of international cooperation has been overshadowed by North Korea's announcement last week that it is planning to carry out a rocket-powered satellite launch in April. Against that tense backdrop, Obama will on Sunday visit the demilitarized zone that splits the Korean Peninsula in two for the first time. He will also meet with some of the 28,500 U.S. troops stationed in South Korea, two of his top national security advisers said Tuesday during a conference call. In a dramatic reminder of the U.S. military presence in South Korea, an American F-16 fighter jet crashed Wednesday near Kunsan airbase on the western coast of South Korea. The jet's pilot safely ejected before the crash, and no casualties were reported, said Maj. Eric Badger, public affairs officer of the 7th Air Force. Seoul's nuclear summit will be the second after Obama hosted the first meeting in Washington in 2010. He initiated the biennial summit after presenting his vision of a nuclear-free world in Prague in April 2009. Although North Korea is not on the agenda, it is likely to be discussed on the sidelines. Pyongyang announced earlier this month it would carry out a "satellite launch" in mid-April to commemorate the centenary of the birth of Kim Il Sung, the country's founder. Using ballistic missile technology, however, is in violation of U.N. Security Council Resolution 1874 and against a deal struck with the United States earlier this month that it would not carry out nuclear or missile tests in return for food aid. Pyongyang has said it will see any critical statement of its nuclear program as "a declaration of war." CNN's Paula Hancocks, Jethro Mullen and Bob Kovach contributed to this report.