North Korea had reportedly asked for huge sums in cash in return for halting its exports of missiles during negotiations with the U.S. government in the late 1990s.

According to declassified U.S. State Department documents obtained by Japan’s Kyodo News Agency, North Korea tried to use its missile development and exports as a bargaining chip for economic benefits in negotiations.

The news agency said during negotiations in October 1998, North Korea demanded one billion dollars from the Clinton administration annually for three years in exchange for halting its overseas missile exports.