White House spokesman Tony Snow said there would be no bilateral talks with North Korea, and any negotiations will take place within a six-nation framework.
North Korea had made the invitation with the condition that the United States relax its financial restrictions on Pyongyang.
DECLARED NUCLEAR-WEAPONS COUNTRIES:
country warheads (est.) date of first test
United States 10,500 1945
Russia 18,000 1949
United Kingdom 200 1952
France 350 1960
China 400 1964
India 60-90 1974
Pakistan 28-48 1998
North Korea 0-18 2006
Israel is widely believed to possess nuclear weapons, but it has not declared itself a nuclear-armed country.
South Africa constructed six uranium bombs but voluntarily dismantled them.
Belarus, Kazakhstan, and Ukraine all gave up the nuclear weapons that were on their territory when the Soviet Union collapsed in 1991.