SEOUL — 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 UN Security Council agreed to a US-backed resolution to censure and sanction North Korea for a rocket launch in December that breached UN rules. North Korea is not believed to have the technology to deliver a nuclear warhead capable of hitting the continental United States, although its December launch showed it had the capacity to deliver a rocket that could travel 10,000 km (6,200 miles), potentially putting San Francisco in range, according to an intelligence assessment by South Korea. “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 Defense 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 UN sanctions. China, the one major diplomatic ally of the isolated and impoverished North, agreed to the US-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. Washington urged North Korea not to proceed with a third test just as the North's statement was published on Thursday. “Whether North Korea tests or not is up to North Korea,” Glyn Davies, the top US envoy for North Korean diplomacy, said in the South Korean capital of Seoul. “We hope they don't do it. We call on them not to do it,” Davies said after a meeting with South Korean officials. “This is not a moment to increase tensions on the Korean Peninsula.” — Reuters