North Korea's resumption of its nuclear weapons program has set its neighbors and much of the rest of the world on edge.

Five nations -- the United States, China, Russia, Japan and South Korea -- are now piling the pressure on North Korea to curb its nuclear ambitions.

Pyongyang has said it wants a formal non-aggression treaty with the United States before it makes any move. But lately it has been dishing out a charm offensive in a bid to get Washington to be more flexible.

For its part, the United States is keen to see the standoff resolved but is standing firm amid concerns expressed by top officials that the nation is a "rogue state" holding the world hostage to nuclear blackmail.