According to reports, North Korea will soon be testing a nuclear warhead along with ballistic missile tests on missiles that could carry a nuclear warhead as its payload. The White House hailed the resolution a "strong message to Pyongyang" but North Korea launched missiles off its east coast just hours later.
Kim Jong Un warned of the impending tests on Tuesday, saying they served "to further enhance the reliance of nuclear attack capability", according to the Korean Central News Agency (KCNA). North Korea describes the exercises, which run through the end of April, as a precursor for invasion.
China, North Korea's most important ally, has reaffirmed its commitment to fully implement United Nations sanctions against Pyongyang over its recent nuclear tests and missile launches.
"What would be terrible is if the DPRK (North Korea) re-enacted Operation Frigate Bird or the fourth Chinese nuclear test and did a two-in-one", said Jeffrey Lewis of the California-based Middlebury Institute of International Studies.
The threats add weight to speculation that the North may carry out more nuke and missile provocations following its nuclear test and long-range rocket launch earlier this year.
In January, North Korea claimed to have test-fired the nation's first hydrogen bomb. Spokesman Moon Sang Gyun said the assessment is based on an analysis of South Korean and United States intelligence. Even though the missile capabilities of North Korea is in question, the United States still issued a statement urging caution.
How advanced is North's nuclear programme? The claims were accompanied by pictures of the leader standing alongside what state media said was a miniaturised nuclear warhead.
He has been quoted as ordering the production of more nuclear bombs and preparations for using them on short notice, including possible pre-emptive attacks, and making threats to turn South Korea, the USA mainland and United States bases in the Pacific into a "sea of fire and ashes".
China tested a medium-range ballistic missile with a 12-kiloton nuclear warhead in 1996, the only time a country has flight-tested a nuclear-tipped ballistic missile over populated areas. It would be very dicey, very destabilising,' Hanham said.