North Korea has agreed to permit the return of UN nuclear inspectors as part of a package of measures to ease acute tensions on the peninsula, U.S. troubleshooter Bill Richardson said Monday.

In a statement issued as he visited Pyongyang, Richardson said North Korean leaders also agreed to negotiate the sale of nuclear fuel rods to a third party, "such as South Korea", and to discuss a military commission and hotline.

Richardson, a former U.S. ambassador to the UN, said also he was "very encouraged" that North Korea's military had forsaken retaliation after South Korean forces held a live-fire artillery drill on a flashpoint border island.

"During my meetings in
Pyongyang , I repeatedly pressed North Korea not to retaliate," the New Mexico governor said.

"The result is that
South Korea was able to flex its muscles, and North Korea reacted in a statesmanlike manner. I hope this will signal a new chapter and a round of dialogue to lessen tension on the Korean peninsula," he said.

Confirming a CNN report,
Richardson 's statement said Pyongyang had agreed to allow the return of inspectors from the UN's International Atomic Energy Agency (IAEA).

North Korea in April 2009 pulled out of six-nation nuclear disarmament talks and ordered U.S. and IAEA nuclear inspectors out of the country, after the UN Security Council condemned Pyongyang for an April 5 rocket launch.

It staged its second nuclear test a month later.

Tensions have soared anew since a North Korean artillery attack last month on the South Korean
island of Yeonpyeong , which killed four people including civilians and damaged dozens of homes.

In addition, the North's disclosure last month of a new uranium enrichment plant in addition to its longstanding plutonium operation has sparked fears of a potential new source of bomb-making material.

Richardson said the North Koreans would allow "IAEA monitors access to North Korea 's uranium enrichment facility".

They were also prepared to negotiate "a deal for a third party, such as
South Korea , to buy fresh-fuel rods from North Korea ".

They would discuss the military commission, grouping representatives from the two
Koreas plus the United States , "to monitor and prevent conflicts in the disputed areas of the West (Yellow) Sea".

And they were ready to create "a hotline between the North Korean and South Korean militaries to avert potential crises",
Richardson 's statement said.

In
Pyongyang over the weekend, Richardson met top nuclear negotiator Kim Kye-Gwan and Major General Pak Rim-Su, who leads North Korean forces along the tense border with the South.

Richardson was due to brief reporters in Beijing on Tuesday, after his flight out of Pyongyang was cancelled on Monday owing to bad weather.