BEIJING -- North Korea pledged Thursday to carry out long-range rocket launches and another nuclear test, a series of moves that would defy United Nations sanctions and further ratchet up tensions in the region.

The announcement by North Korea’s National Defense Commission came just two days after the U.N. Security Council condemned Pyongyang’s December satellite launch, which was widely seen as a thinly disguised test of ballistic missile technology. In addition to adding more North Korean officials, businesses and committees to a travel ban and asset freeze, the United Nations had pledged Tuesday to “to take significant action” in the event of a further North Korean launch or nuclear test.

Pyongyang didn’t appear to be swayed. In a rambling statement Thursday carried by North Korea’s official news agency, the National Defense Commission said that, “we do not hide that a variety of satellites and long-range rockets which will be launched by the DPRK” – the Democratic People’s Republic of Korea – “one after another and a nuclear test of higher level which will be carried out by it in the upcoming all-out action . . . will target against the U.S., the sworn enemy of the Korean people.”

It added: “Settling accounts with the U.S. needs to be done with force, not with words.”

What exactly the commission, which is headed by young North Korean leader Kim Jong Un, meant by “target against the U.S.” was unclear. The nation is thought not to have the ability to build a nuclear warhead that could fit the tip of an intercontinental missile capable of hitting the United States. The “higher level” of nuclear test might be in reference to working toward solving that dilemma.

The Obama administration condemned the North Korean announcement and warned that any nuclear test would trigger new U.N. action and further international isolation for Pyongyang.

"North Korea’s statement is needlessly provocative, and a test would be a significant violation of United Nations Security Council resolutions," White House spokesman Jay Carney said. "Further provocation would only increase Pyongyang’s isolation, and its continued focus on its nuclear and missile program is doing nothing to help the North Korean people."

He continued: "We judge North Korea by its actions, and provocations like these are significant violations, and we act accordingly."

Secretary of Defense Leon Panetta said at a briefing Thursday at the Pentagon that he was "very concerned" about reports coming out of North Korea but hasn’t seen outward signs that the country is preparing for a nuclear test.

In moves that could further anger North Korea, the United States announced that it was placing on its U.S. sanctions list four North Korean entities and four officials, including two North Korean bank representatives based in China, for alleged involvement in the Stalinist country’s ballistic missile program.

While it’s often difficult to parse North Korea’s threats from rhetorical bluster – for example, it’s spoken in the past of unleashing “a sea of fire” on South Korea – the prospect of a nuclear test fits with a warning that Seoul issued this week.

On Wednesday, South Korea’s Yonhap news service cited an intelligence source as reporting that North Korea had completed preparations for a nuclear test.