North Korea is extremely close to producing a long-awaited accounting of its shuttered nuclear program, a senior U.S. official said Friday. The documentation would be a major step toward a disarmament deal with the reclusive communist regime.

Although there is no date agreed yet, the documentation is expected within the next month. That would clear the way for a high-stakes meeting as soon as the end of June between the top U.S. and North Korean diplomats, along with the other four nations involved in a deal to put North Korea out of the nuclear weapons business.

The official, who spoke on condition of anonymity because the six-nation diplomatic consultations are confidential, says the U.S. insists it be able to verify that North Korea's documentation is complete.

The official says that weeks of preparation with North Korea, South Korea, Japan, China and Russia are coming to a close.

The administration's top negotiator for North Korea will travel to China and Russia next week for the final preparatory meetings before the North hands over its paperwork.

Senior U.S. officials said that while in China, Assistant Secretary of State Christopher Hill will meet with his North Korean counterpart.

Hill met earlier this week in Washington with Japanese and South Korea diplomats involved in the disarmament talks. Those sessions were considered the most difficult hurdles before the group can formally receive North Korea's nuclear accounting and reciprocate with promised concessions. Japan wants further assurances that North Korea is serious about investigating allegations that it abducted Japanese citizens, and a new government in South Korea has taken a much tougher line on relations with the North.

With those meetings out of the way, State Department spokesman Tom Casey said Hill will brief the Chinese and Russians.

China is the North's closest ally and the host of the six-nation talks. As host, China is the nation to which the North will formally present the documentation.

The Bush administration rejected a Clinton-era nuclear deal and diplomatic outreach to Pyongyang, and has shunned the North for much of President Bush's time in office. The expected meeting between U.S. Secretary of State Condoleezza Rice and North Korea's top diplomat would mark a major turnaround in relations with a state Bush once labeled part of an "axis of evil."

North Korea said it needed a strong deterrent to ward off a possible U.S. invasion, and exploded a nuclear device in 2006, before agreeing to trade away is nuclear weapons program for economic and political concessions from Asia and the West.

One of the first requirements for the North was a detailed technical accounting of its plutonium program, including the amount of weapons-grade plutonium produced at a now-shuttered reactor.

The United States says the North missed a Dec. 31, 2007 deadline to come up with that paperwork. U.S. officials say the North produced only a partial accounting last fall but is now ready to turn over all the information that the United States and its partners need.

The United States has promised that after the accounting is in and checked it will remove North Korea from a State Department list of nations that sponsor terrorism. Lifting the terror stigma is a special goal of North Korean leader Kim Jong Il. Under the schedule U.S. officials expect, the United States could grant that concession in June.