North Korea said on Saturday it would start a uranium enrichment programme and vowed to weaponise all of its plutonium in response to U.N. punishment for its nuclear test.
Pyongyang also threatened military action if the United States and its allies tried to isolate it.
The Security Council approved a resolution on Friday which banned all weapons exports from North Korea and most arms imports into the state. It authorised U.N. member states to inspect North Korean sea, air and land cargo, requiring them to seize and destroy goods shipped that violate the sanctions.
"We'll take firm military action if the United States and its allies try to isolate us," KCNA news agency quoted an unnamed Foreign Ministry spokesman as saying in a statement. Read more.