Declassified documents from the U.S. Central Intelligence Agency (CIA) show that South Korea pursued the development of nuclear weapons until at least 1978 as opposed to the general view that it ended its pursuit 1976.

U.S. defense think tank the Nautilus Institute says a CIA document dated September fifth, 1978 includes a remark made by then South Korean Foreign Minister Park Dong-jin.

Park was quoted as saying in May 1977 that if the U.S. withdrew tactical nuclear weapons from South Korea, the Seoul government would consider its own nuclear development.

The think tank says that the CIA believed talks of nuclear development within South Korea had to do with the possible pullout of U.S. troops, and the South Koreans considered a U.S. nuclear umbrella as an important means to deter war on the Korean Peninsula.

But the U.S. intelligence agency said in the 1978 document that no concrete evidence regarding development of nuclear weapons was found.