Robert King, the U.S. special envoy for North Korean human rights issues, is meeting representatives from Pyongyang to finalize points like what ports will be used to dock incoming ships, how the distribution of the food will be monitored and which nongovernmental organizations will be involved.
"We've made progress," King said Wednesday after two sessions of talks. "We still have issues to resolve and will be meeting tomorrow to deal with those issues."
North Korea last week announced an agreement to freeze its nuclear and missile tests, along with uranium enrichment programs, and allow the return of U.N. nuclear inspectors. The United States said it would provide 240,000 metric tons of nutritional assistance to the impoverished country.
The United States had suspended shipments of food aid to North Korea in 2009 amid tensions over Pyongyang's nuclear program and concerns that the supplies were not reaching those most in need.
The deal last week to resume the deliveries came after the the two countries revived negotiations that had stalled after the death in December of the longtime North Korean leader Kim Jong Il.
The talks this week should be the final phase in implementing U.S. food aid, according to Victoria Nuland, the U.S. State Department spokeswoman.
Nuland said Wednesday that she hoped this round of negotiations would succeed in settling the details "because we'd like to move this, this nutritional assistance."
The initial agreement last week was cautiously welcomed by U.S. officials in the hope that a new era in relations with the North would begin and lead to a resumption of multilateral talks aimed at the denuclearization of the Korean peninsula.
But Pyongyang has stepped up its rhetoric against the South Korean president, Lee Myung-bak, and his government since Kim Jong Un took over from his father, Kim Jong Il, as North Korean leader.
Earlier this week, North Korean television aired footage of a military unit carrying out live-fire drills in sight of a South Korean island.
It showed tanks repositioning and an artillery machine being prepared, overlooking waters that have seen a number of violent incidents over the years. North Korea shelled Yeonpyeong Island in November 2010, killing four South Koreans, claiming it was responding to a South Korean military drill in the area.
Li Gum-chol, a North Korean deputy commander, said: "We will turn Seoul into a sea of flames by our strong and cruel artillery firepower, which cannot be compared to our artillery shelling on Yeonpyeong Island. We are training hard, concentrating on revenge to shock Lee Myung-bak's traitorous group and the military warmongers in South Korea."
The United States and South Korea are carrying out annual joint military drills, which North Korea has condemned as a provocation. Now, Pyongyang is staging its own.