Ottawa, 15 June-(ANA)-North Korea's threat to "weaponise" its plutonium stocks is "provocative" and "deeply regrettable", US Secretary of State Hillary Clinton has said.
Mrs Clinton said the move had been denounced around the world and would isolate North Korea's government further.
The North said it would start enriching uranium and use the plutonium for nuclear weapons hours after a UN vote for tough new sanctions against it.
The US would vigorously enforce the new sanctions, Mrs Clinton said.
Speaking during a visit to Canada, she said that the latest UN moves provided the tools needed for "to take appropriate action" against North Korea.
The North says it will view any US-led attempts to "blockade" it as an "act of war".
The warning from North Korea's foreign ministry was carried by Pyongyang's official news agency on Saturday.
On Friday, the United Nations Security Council voted unanimously to impose tougher sanctions on the communist North, after its nuclear test on 25 May.
The UN sanctions include the inspection of North Korean ships, a wider ban on arms sales and other financial measures.
The US says the new sanctions show a strong and united response to North Korea's "unacceptable behaviour". (ANA)
Amnesty/Report