They also want to fire off a few long range rockets. And they claim all this bellicosity is "targeted" at the US.
North Korea said on Thursday it would carry out further rocket launches and a nuclear test that would target the United States, dramatically stepping up its threats against a country it called its "sworn enemy".
The announcement by the country's top military body came a day after the U.N. Security Council agreed to a U.S.-backed resolution to censure and sanction North Korea for a rocket launch in December that breached U.N. rules.
"We are not disguising the fact that the various satellites and long-range rockets that we will fire and the high-level nuclear test we will carry out are targeted at the United States," North Korea's National Defence Commission said, according to state news agency KCNA.
North Korea is believed by South Korea and other observers to be "technically ready" for a third nuclear test, and the decision to go ahead rests with leader Kim Jong-un who pressed ahead with the December rocket launch in defiance of the U.N. sanctions.
China, the one major diplomatic ally of the isolated and impoverished North, agreed to the U.S.-backed resolution and it also supported resolutions in 2006 and 2009 after Pyongyang's two earlier nuclear tests.
Thursday's statement by North Korea represents a huge challenge to Beijing as it undergoes a leadership transition with Xi Jinping due to take office in March.
China's Foreign Ministry called for calm and restraint and a return to six-party talks, but effectively singled out North Korea, urging the "relevant party" not to take any steps that would raise tensions.
"We hope the relevant party can remain calm and act and speak in a cautious and prudent way and not take any steps which may further worsen the situation," ministry spokesman Hong Lei told reporters at a regular press briefing.
North Korea has rejected proposals to restart the talks aimed at reining in its nuclear capacity. The United States, China, Russia, Japan and the two Koreas are the six parties involved.
Surprised that China sided with the west in UN condemnation of the NoKos? Don't be. They were successful - as they always are - in watering down the sanctions and you can imagine the hurt feelings in Pyongyang over a UN resolution condemning them.
China's interest in North Korea is mostly practical. While they might enjoy supporting a nation that continuously pokes the US in the side, and have feelings of solidarity with their socialist brothers, the primary interest of the Chinese is a stable, economically healthy North Korea. China has a refugee problem on their border with the NoKos as people flee the starvation and oppression. Not enamored of foreigners in the first place, the NoKo refugees are a potential source of unrest and the Chinese believe that halting the North Korean nuclear program will aid the economy and put food in the bellies of peasants.
They're right, but it's obvious that the North Koreans aren't listening.