(J. Scott Applewhite ~ Associated Press)
The simultaneous announcements in Pyongyang and Washington pointed toward an easing of nuclear tensions under new leader Kim Jong Un and could clear the way for resumption of the multination disarmament-for-aid talks that the North withdrew from in 2009.
The accord also opens the way for international nuclear inspections after years when the North's program went unmonitored.
Secretary of State Hillary Rodham Clinton called the North Korean announcement a "modest first step" but also "a reminder that the world is transforming around us."
Coming just over two months after the death of longtime ruler Kim Jong Il, the accord seemed to signal a willingness by the reclusive North Korean government to improve ties with the U.S. and win critical assistance. It still falls far short of an agreement to abandon the nuclear weapons program that Pyongyang has seemed to view as key to the government's survival.
In a key concession, North Korea said it had agreed to allow International Atomic Energy Agency inspectors to verify and monitor a moratorium on uranium enrichment activities at its main Yongbyon nuclear complex, a program that the North unveiled to visiting U.S. academics in 2010.
Uranium enrichment could give it a second route to manufacture nuclear weapons, in addition to its existing plutonium-based program. At low levels, uranium can be used in power reactors, but at higher levels it can be used in nuclear bombs. The North has conducted two nuclear tests since 2006 and has conducted a long-range rocket test, in defiance of United Nations Security Council resolutions.
IAEA monitors will also confirm disablement of a nuclear reactor at Yongbyon and associated facilities, the U.S. said.
Clinton said the United States will meet with North Korea to finalize details for a proposed package of 240,000 metric tons of food aid, referring to it as "nutritional assistance." She said that intensive monitoring of the aid would be required -- a reflection of U.S. concerns that food could be diverted to the North's powerful military. The U.S. said there was the prospect of additional assistance based on continued need.
North Korea suffered famine in the 1990s and appealed for the aid a year ago to alleviate chronic food shortages.
The North's statement on the agreement was issued by its state-run news agency. It was slightly different, but released at the same time as the U.S. announcement.
An unidentified spokesman from North Korea's Foreign Ministry was quoted saying the North agreed to the nuclear moratoriums and the allowance of U.N. inspectors "with a view to maintaining positive atmosphere" for the U.S.-North Korea talks.
The U.S. still has nearly 30,000 troops based in South Korea, a legacy of the 1950-1953 Korean War. The war ended in an armistice rather than a peace treaty, leaving the divided Korean peninsula formally in a state of war.
Wednesday's announcement followed talks in Beijing last week between U.S. and North Korean negotiators, the first since negotiations were suspended after Kim Jong Il's death in December from a heart attack.
Before Kim's death, the U.S. and North Korea were close to the agreement, which appears to meet U.S. preconditions for restarting the broader six-nation talks suspended three years ago. The talks also include China, Japan, Russia and South Korea.
Outsiders have been closely watching how the younger Kim, believed to be in his late 20s, handles nuclear diplomacy with the United States and delicate relations with rival South Korea. His consolidation of power, with the help of a group of senior advisers who worked with his father and grandfather, appears to be going smoothly, although determining the intentions and internal dynamics in Pyongyang is notoriously difficult.
Since Kim Jong Il's death, North Korea has vowed to maintain the late leader's policies and has linked its nuclear program to Kim's legacy. Many observers are skeptical whether North Korea will ever give up its nuclear program.
"North Korea uses [the nuclear program] as leverage to win concessions in return for disarmament measures. Since Kim Jong Il's death, it has called (the program) the country's most important achievement," Baek Seung-joo, an analyst at the state-run Korea Institute for Defense Analyses in South Korea, said. "There is still a long way to go."
South Korea welcomed the agreement. Foreign Ministry spokesman Cho Byung-jae said it reflected the close work Seoul and Washington have done to try to resolve the nuclear standoff.
The U.S. said it had no hostile intent toward North Korea and was prepared to increase people-to-people exchanges, including in the areas of culture, education, and sports.
"The United States still has profound concerns but on the occasion of Kim Jong Il's death I said it is our hope that the new leadership will choose to guide their nation on to path of peace by living up it to its obligations," Clinton said.
She said the United States will judge the new government by its actions.
There were some differences in the U.S. and North Korean statements on the nuclear moratoriums.
The U.S. said North Korea has agreed to a moratorium on "nuclear activities" at Yongbyon, including uranium enrichment, while the North Korean statement referred only to uranium enrichment. It was not immediately clear if that implied the plutonium-based program would remain.
A senior Obama administration official acknowledged that omission in the North Korean statement but said the U.S. was in no doubt that the North has agreed to let international inspectors into its plutonium facility at Yongbyon.
The official, speaking to reporters on condition of anonymity because of diplomatic sensitivities, said it was up to North Korea to contact the U.N. nuclear watchdog, but the U.S. had alerted the Vienna-based agency of its agreement with Pyongyang.
The IAEA confirmed it was ready to return to Yongbyon to do monitoring when requested by its board of governors.
The North said that once six-nation nuclear talks are resumed, "priority will be given to the discussion of issues concerning the lifting of sanctions on the [North] and provision of light water reactors." Those details were not included in the U.S. statement.
Although the North has conducted two nuclear tests and has developed a battery of ballistic missiles, it says it is constructing its own light water reactor to generate electricity to alleviate chronic power shortages.