The Bush administration urged North Korea on Tuesday not to spring any nuclear surprises next month, ahead of the US presidential election, and warned it would consider going back to the UN Security Council if denuclearisation talks remained stalled.

John Bolton, undersecretary for arms control and international security, was responding to remarks made at the United Nations by a North Korean official who said the communist state had reprocessed 8,000 spent fuel rods “and transformed them into arms”.