BEIJING - North Korea is committed to closing its main nuclear reactor within a month as long as Washington meets a promise to drop financial sanctions, the chief UN nuclear inspector said Wednesday after a one-day trip to Pyongyang.

International Atomic Energy Agency head Mohamed ElBaradei offered an encouraging assessment of the month-old nuclear disarmament pact, saying North Korean officials told him they were "fully committed" to implementing the deal to shut the reactor and welcome back UN inspectors.

The officials said they were "ready to work with the agency to make sure that we monitor and verify the shutdown of the Yongbyon" nuclear reactor, ElBaradei told reporters after the first IAEA visit to North Korea since its inspectors were kicked out four years ago.

He added, however, that the deal between the U.S., North Korea and four other countries was still "fragile."

The Yongbyon reactor is believed to have produced plutonium for North Korea's nuclear test blast on Oct. 9.

North Korean officials told ElBaradei they were waiting for the United States to drop financial sanctions that include a freeze on overseas assets, he said.

"The agreement is still quite fragile, precarious, so I hope all parties will see to it we continue to solidify that agreement," he said.

A particularly sore spot for the North Korean government has been the freezing of accounts in a bank in the semiautonomous Chinese territory of Macau, which include what the Bush administration says are more than $25 million in North Korean assets.

The U.S. had alleged that Banco Delta Asia helped North Korea distribute counterfeit currency and engage in other illicit activities, prompting banks around the world to worry about dealing with the Macau institution.

The Bush administration said Wednesday it will order U.S. banks to sever ties with Banco Delta Asia, a measure that could in fact help the bank by replacing the blanket allegations with a definitive and limited U.S. restriction.

The Treasury Department also is expected to help overseas regulators identify individual account holders' risk of involvement in illicit activities. This assessment could be used by Macau to release money that has been frozen.

"Until we see what the U.S. is doing on the banking sanctions and how North Korea reacts to that we really must be very cautious about whether they will shut down the reactor," said Selig Harrison, director of the Asia program at the Washington-based Center for International Policy.

"This is the most serious threat to the Feb. 13 agreement," he said. "The whole thing could bog down on that issue very easily."

ElBaradei was originally meant to meet with the North's chief nuclear negotiator, Kim Gye Kwan, but the schedule was changed at the last minute. ElBaradei dismissed concerns that he had been snubbed.

Kim "was sick, he fell ill after coming back from New York," ElBaradei said. "It is not true that he was too busy."

ElBaradei met instead with another vice foreign minister of the same rank, Kim Hyong Jun, as well as Ri Je Son, head of the North's General Bureau of Atomic Energy and Kim Yong Dai, vice president of the Supreme People's Assembly.

Harrison said Kim's failure to meet with ElBaradei was probably not a signal of reluctance to cooperate with the agency. In the past, IAEA delegates visiting North Korea would not expect to meet with high Foreign Ministry officials, meeting instead with Atomic Agency officials.

International talks are to begin Monday in Beijing among the United States, North Korea, South Korea, Japan, Russia and China to examine progress in implementing the Feb. 13 deal.

The countries also plan over the weekend to discuss economic and energy cooperation, peace and security in Northeast Asia and the denuclearization of the Korean Peninsula as part of the landmark pact.

The North Korean nuclear crisis began in 2002, when Washington alleged that Pyongyang had a uranium enrichment program in addition to its acknowledged plutonium program. North Korea then withdrew from the Nuclear Nonproliferation Treaty and expelled ElBaradei's inspectors.

ElBaradei said he was told that getting North Korea back into the Nuclear Nonproliferation Treaty -- it withdrew in January 2003 -- would be a slow, incremental process.

"All we can do now is make sure the process does not derail," he said.

The North is to eventually receive 1 million tons of heavy fuel oil for abandoning all its nuclear programs. U.S. officials have stressed this must include an alleged uranium enrichment program, which the North has never publicly admitted having.