WASHINGTON, Sept 8 (AFP) - South Korea may have been involved in illicit nuclear activity even before its unauthorized experiment to enrich uranium four years ago and currently under probe by the UN nuclear watchdog, the United States said Wednesday.
"Our understanding is that over 20 years ago, the South Koreans did experiments involving trace amounts of plutonium," a senior US official said, speaking on condition of anonymity.
Highly enriched uranium and plutonium could be used to make nuclear bombs.
Seoul last week admitted South Korean scientists had carried out an unauthorised experiment to enrich uranium four years ago but says it was not linked to any weapons program.
The experiment conducted in January 2000 at the country's state-run nuclear research center produced a minuscule amount of enriched uranium, it said.
The International Atomic Energy Agency team went to South Korea to carry out a probe last week and its findings will be discussed at a four-day board meeting of the nuclear watchdog starting Monday.