North Korea vowed to boost its nuclear capabilities on Wednesday after the United Nations Security Council unanimously passed a resolution condemning its controversial rocket launch last December.

“The present situation clearly proves that (North Korea) should counter the U.S. hostile policy with strength, not with words,” the country’s foreign ministry warned in a statement.

North Korea pledged in the statement to bolster its military capabilities and to build up what it called a “nuclear deterrence." 

It also defended its “independent and legitimate right” to launch satellites and condemned the U.N. resolution as a “wanton violation of the inviolable sovereignty of (North Korea).”

The U.N. resolution passed on Tuesday called on North Korea to abandon its nuclear program and cease rocket launches, and came a month after the country, officially known as Democratic People's Republic of Korea, successfully conducted a rocket launch that put a satellite into orbit.

Pyongyang maintains that the test was purely “for peaceful purposes.”

U.S. officials disagree, saying the test was the latest attempt to develop multistage ballistic missiles capable of carrying nuclear warheads.

Washington hopes the newest U.N. resolution will help bind world opinion against North Korea’s opaque nuclear program.

"This resolution demonstrates to North Korea that there are unanimous and significant consequences for its flagrant violation of its obligations under previous resolutions," American ambassador to the United Nations, Susan Rice, told reporters after the vote.

China’s unusual support for the resolution, the first in four years to expand sanctions against North Korea, suggests Beijing’s patience with its troublesome neighbor may be fraying. 

But in comments made after the vote, Li Baodong, China's ambassador to the U.N., warned sanctions alone would not resolve the impasse.

“The policy of the sanction does not work,” he said. “The resolution must be accompanied, supplemented by diplomatic efforts.”

The new sanctions were categorized under the scope of existing ones, which were expanded to include North Korean government agencies -- most notably the North Korean Space Agency -- and companies.

In addition, a list of nuclear and ballistic missile technology banned for export to North Korea has been updated.

Despite the resolution and international concerns about North Korea’s nuclear program, leading North Korea expert Wang Junsheng said it was unlikely that Pyongyang would conduct a nuclear test anytime soon.

“(North Korea) uses nuclear tests to negotiate with foreign countries but mainly to establish the Kim family's stature within the country,” he said, referring to the country’s ruling family.

“By successfully launching the satellite last month, there is no need for Kim Jong Un to conduct a nuclear test at this time,” he said. 

Kim Jong Un, North Korea’s supreme leader, is the son of Kim Jong Il and grandson of Kim Il Sung, who founded the communist state.

NBC News' Li Le contributed to this report.

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