North Korea moved closer to restarting its nuclear arms program Sept. 24, barring U.N. inspectors from its main plutonium reprocessing plant and announcing it will reactivate the facility that provided the material for its atomic test blast.

The move fed fears about a resurgent nuclear North Korea, but there also is speculation it might be motivated by negotiating strategy. Pyongyang could use the year needed to restart its sole reprocessing plant to wrest more concessions from the United States and others seeking to end the atomic program.

Still the nuclear reversal is raising nervousness about a breakdown in international talks.