North Korea has acknowledged that it has a secret nuclear weapons programme, US government officials have reported.

The Communist state's admission places it in violation of a 1994 agreement signed with the administration of former US President Bill Clinton, under which Pyongyang agreed to freeze its nuclear programme.

Reclusive North Korea is one of three states dubbed an "axis of evil" by US President George W Bush, along with Iran and Iraq.

However, in recent months there has been a thawing in Pyongyang's dealings with the outside world.

Earlier this month Mr Bush sent Assistant Secretary of State James Kelly to North Korea for security talks.

Response

North Korea reportedly confessed to its nuclear programme after being confronted with American documentary "evidence" on the issue by Mr Kelly during his visit.

At first the North Koreans tried to deny the evidence, but eventually "they acknowledged they had a secret nuclear weapons programme involving enriched uranium," one official said.

"By acknowledging that, the agreed framework was essentially nullified," he said, referring to the 1994 Agreed Framework under which in return for halting its weapons programme North Korea was given US assistance in building two light water reactors.

US officials have said that the Bush administration is now consulting with its allies and Congress before deciding what to do in light of the revelation.