The North Korean announcement, carried by the Stalinist regime's official news agency, appeared to give Pyongyang some room to pull back, saying it would observe the moratoriums "while productive dialogues continue."
The State Department noted that "the United States still has profound concerns regarding North Korean behavior across a wide range of areas." But it added that the agreement "reflects important, if limited, progress in addressing some" U.S. concerns.
That opened the way for finalizing the details of delivering about 264,000 tons of badly needed U.S. food aid to North Korea. The two sides also will discuss monitoring delivery of the aid, which Washington apparently is demanding to ensure that it reaches civilians and isn't diverted to the North Korean military.
A second senior administration official, who also briefed reporters on the condition of anonymity, said the food aid would be delivered in batches of about 20,000 tons per month for 12 months, with an emphasis on the country's most vulnerable citizens: children, pregnant women and the elderly.
He said the deliveries wouldn't begin until the monitoring program was in place.
This will be "the most comprehensively monitored and managed program since the U.S. began assistance to (North Korea) in the mid-1990s," he said.
According to a U.N. World Food Program report in November, the impoverished Stalinist nation of 25 million people is suffering a shortage estimated at more than 451,900 tons of food.
Malnutrition and health problems are rampant, according to the report, creating a potential source of instability for the young Kim — who's thought to be in his mid-20s — as he and a tight circle of veteran aides strive to consolidate his power after his father's death.
While the Obama administration says it doesn't link food aid to the effort to restart the six-party talks — which involve the U.S., China, Russia, Japan, South Korea and North Korea — some experts said that was precisely what it had done in the new deal.
"They can walk away from a moratorium anytime they want after they get the food," said Mitchell Reiss, a retired U.S. ambassador who participated in nuclear negotiations with the North Koreans. He's a foreign policy adviser to GOP presidential candidate Mitt Romney, but he said he was speaking in his personal capacity.
The six-party talks began in August 2003, and after four rounds they succeeded in forging a 2005 agreement requiring Pyongyang to end its nuclear program in exchange for massive financial and energy assistance, and establishing diplomatic links to the outside world.
In October 2006, North Korea conducted an underground nuclear test, triggering U.N. sanctions. It declared an end to the six-party talks in July 2009, three months after a second underground nuclear test and a series of ballistic missile tests in violation of a U.N. resolution.
The State Department announcement said that as part of the new deal, the U.S. "reaffirms that it does not have hostile intent" toward North Korea.
Some experts noted that there was no reference to hostile North Korean actions against South Korea, including a March 2010 torpedoing of a South Korean naval ship that killed 46 sailors and an artillery barrage of a South Korean island eight months later that killed four South Koreans. In another potential flaw to the agreement, there's considerable suspicion that North Korea is hiding its main uranium-enrichment facility.
"The enrichment we're concerned about doesn't take place at Yongbyon," Reiss said, declining to elaborate.
(Lesley Clark contributed to this article.)
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