The agreement came during recent talks in Beijing, diplomatic sources in Seoul told Yonhap News Agency Saturday.
North Korea's pledge could help improve the chances of progress during nuclear negotiations set for later this month.
Yonhap reported the two sides said they had "reached the agreement based on North Korea's pledge to implement initial measures of denuclearization that include a suspension of its uranium-enrichment program."
The agreement came during two days of meetings between Robert King, U.S. special envoy on North Korean human rights, and Ri Kun, director general for North American affairs at North Korea's Foreign Ministry, Yonhap said.
King told reporters Friday the talks were "constructive."
The U.S. food aid will be delivered in shipments of 20,000 tons for the next 12 months, sources told the news agency.
North Korea, facing chronic food shortages, reportedly requested rice, but sources in Seoul said U.S. aid will be largely biscuits and vitamin supplements for infants.
U.S. officials have long suspected food aid to North Korea, especially rice, may be diverted to the country's military.
A source said North Korea had also agreed to "address the United States' monitoring concerns" regarding the North's nuclear program.
The two countries are to begin a new round of talks Thursday aimed at restarting the six-nation negotiations on ending North Korea's nuclear ambitions. The six-way talks -- also involving South Korea, Japan, China and Russia -- have stalled since late 2008.
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