US will not accept N Korea as a nuclear state: White House

The United States will not accept North Korea as a nuclear power, the White House has asserted, as the Pentagon took steps along with its regional allies to thwart off any misadventure from Pyongyang.

"The United States will not accept North Korea as a nuclear state, nor will we stand by while it seeks to develop a nuclear-armed missile that can target the United States," White House Press Secretary Jay Carney told reporters on Monday.

The US, he said, has decided to beef up its missile defense system in view of the increasing threat from North Korea.

"We continue to work with all of our allies and partners on this issue to pressure and isolate North Korea, to make clear to North Korea what its options are and how it needs to proceed in order to rejoin the community of nations. And our position is quite firm on that," he said.

Noting that US President Barack Obama and his national security team is  focused on this issue, Carney said the US leadership at the United Nations Security Council, a resolution sanctioning North Korea passed unanimously with Russian and Chinese support, is not an insignificant occurrence.

"The fact of the matter is we remain committed to ensuring peace and stability on the Korean Peninsula. And this means deterring North Korean aggression, protecting our allies, and the complete denuclearisation of the Korean Peninsula," he said.

Earlier in the day, Pentagon Press Secretary George Little said the US is committed to ensuring peace and stability on the Korean peninsula.