Leaders of more than 50 nations and international organizations will focus on crafting measures to secure nuclear and radioactive materials that could pose a danger to the world if handled improperly when they meet in Seoul next week, the U.S. said Thursday.

The State Department made clear that its main aim is to tackle nuclear smuggling.

"The goal of the United States Government's nuclear security programs is the prevention of the illegal possession, use or transfer of nuclear material or other radioactive material," the department said in a news release.

It said the Nuclear Security Summit, to be held in Seoul on Monday and Tuesday, will include discussions over "cooperative measures to combat the threat of nuclear terrorism, protection of nuclear materials and related facilities, and prevention of illicit trafficking of nuclear materials."

President Barack Obama launched the biennial summit in 2010 in an effort to energize international cooperation on securing nuclear materials and preventing nuclear smuggling.

He is scheduled to leave for Seoul on Friday to attend the summit. (Yonhap News)