The United States said Wednesday, February 29 that North Korea has agreed to halt its nuclear program and allow back UN inspectors, in a surprise breakthrough soon after the communist state's veteran leader died, AFP reported.

Welcoming the progress, President Barack Obama's administration said it would move ahead on a long-mulled plan to deliver 240,000 metric tons of food aid to the impoverished state which suffered a major famine in the 1990s.

"The United States still has profound concerns regarding North Korean behavior across a wide range of areas, but today's announcement reflects important, if limited, progress in addressing some of these," State Department spokeswoman Victoria Nuland said in a statement.

Nuland said that North Korea - which has tested two nuclear weapons - has agreed to the return of inspectors from the International Atomic Energy Agency, the UN nuclear watchdog, at its main Yongbyon nuclear facility.

North Korea "has agreed to implement a moratorium on long-range missile launches, nuclear tests and nuclear activities at Yongbyon, including uranium enrichment activities," she said.

The agreement came despite initial US doubts that North Korea would take major decisions after the death in December of veteran leader Kim Jong-Il, which put control of the authoritarian state in the hands of untested young son Kim Jong-Un.