The provocative statement comes weeks after the country conducted underground nuclear tests which caused a massive earthquake.
A foreign ministry spokesman said: “Since the United States is about to ignite a nuclear war, we will be exercising our right to pre-emptive nuclear attack against the headquarters of the aggressor in order to protect our supreme interest.”
However experts doubt the country’s ability to produce a warhead capable of being fitted to a long-range missile.
The UN is set to impose its toughest sanctions yet on Kim Jong-un’s nation – they will be drafted today.
The nuke warning from North Korea was put out by the country’s official news agency and accused the US of leading the calls for the crippling sanctions.
Last month the world was put on high alert when North Korea carried out its biggest nuclear blast yet.
The giant underground explosion caused an earthquake with a magnitude of 4.9.
The successful test took place in the remote, snowy north-east of the country.
The banned blast drew global outrage, even from Pyongyang’s only major ally China.
The actual device was thought to be smaller than those in two earlier tests — raising fears that the crackpot Communist state is close to its aim of perfecting a missile capable of hitting its number one enemy the US.
United Nations chief Ban Ki-moon condemned the explosion, as an emergency meeting of the UN Security Council began drawing up “fresh measures” to punish the rogue country.
In Britain, Foreign Secretary William Hague threatened boy dictator Kim Jong-Un with more “isolation”.
North Korea hit back to say its test was a response to US “hostility”.