In a meeting on Tuesday with North Korea's chief negotiator, Kim Kye-gwan, Hill pressed the idea of a timetable that would conclude the second phase of disarmament by the end of the year.
That would involve North Korea's declaration of all its nuclear activities and permanently disabling Yongbyon.
"We all know that we've got a long road ahead of us with many steps," Hill told reporters. "Maybe we could try to agree on getting these next phase things done in calendar year 07."
There had been no agreement on plans for that phase yet, he said, but North Korea and the United States seemed to be in the same "general vicinity".
South Korea's chief nuclear negotiator, Chun Yung-woo, added his voice to calls for an end-of-year target for finishing the second stage of the North's disarmament.
The third phase would require North Korea handing over fissile nuclear materials and other atomic arms infrastructure.
Japanese envoy Kenichiro Sasae said the onus was on North Korea. "The starting point is to what extent North Korea will respond positively to implement the next steps. First of all, we will listen to North Korea about their ideas and then we will consider how we should respond," Sasae told reporters.
After throwing out IAEA inspectors in late 2002, North Korea quit the nuclear Non-Proliferation Treaty. In 2005, Pyongyang declared it had nuclear arms, and last October it alarmed the world with its first test detonation.
North Korea's official Workers' Party newspaper, Rodong Sinmun, meanwhile said the United States must remove "all nuclear war equipment" from South Korea, illustrating the North's long-held suspicions of hostile U.S. intent.
The United States denies keeping nuclear weapons in the South.
