Scientific tests have led American intelligence agencies and government scientists to conclude with near certainty that North Korea sold processed uranium to Libya, bolstering earlier indications that the reclusive state exported sensitive fuel for atomic weapons, according to officials with access to the intelligence.

The determination, which has circulated among senior government officials in recent weeks, has touched off a hunt to determine if North Korea has also sold uranium to other countries, including Iran and Syria. So far, there is no evidence that such additional transactions took place.