US Secretary of State Condoleezza Rice has welcomed North Korea's decision to allow United Nations nuclear agency inspectors into the country.
The Yongbyon nuclear reactor is set to be shut down
Ms Rice was responding to the IAEA's announcement that it plans to send a team to North Korea next week to shut down its Yongbyon nuclear reactor.
The reactor is due to be closed as part of an international deal to end North Korea's nuclear activities.
The deal was made in February but was then stymied by a financial dispute.
"We know what steps need to be taken to carry out obligations under that agreement," Ms Rice said, referring to the February agreement.
"One of the obligations was to have IAEA inspectors come back to North Korea to participate in the work that it will take to shut down the reactor. It is indeed a good step that that has taken place, or that is about to take place, and we expect North Korea to carry through with its obligations."
She added: "They're on record, and they're not on record just with us. They're on record with the entire region."
Earlier reports from Russia quoted an unnamed North Korean official as saying that Pyongyang plans to shut down Yongbyon in the second half of July.
In a statement, the IAEA said the team would be travelling to Pyongyang in the week beginning on the 25 June.
The visit came at the request of North Korean officials, to "discuss the modalities for verification and monitoring... of the shutdown of the Yongbyon nuclear facility," the statement added.
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Russia's Interfax news agency reported on Monday that the North had set a deadline by which to shut its main nuclear reactor.
"Based on our specialists' evaluations, it will take one month to technically shut down the reactor," a North Korean official was quoted as saying.
"This way, we expect to seal it in accordance with agreements reached at six-party talks in the second half of July 2007."
North Korea initially agreed to "shut down and seal" Yongbyon in exchange for aid, in an historic deal agreed at six-party talks in February.
But a deadline set for April to shut Yongbyon came and went, amid a row over North Korean funds frozen in a Macau bank account.
The US blacklisted the bank, Banco Delta Asia (BDA), in 2005, claiming it was a conduit for North Korean proceeds from drug smuggling and counterfeiting.
Although Washington agreed to release the funds following February's deal, the transfer of the money to North Korea has been held up, in part because banks were unwilling to touch the money.
The breakthrough came towards the end of last week when the money finally moved from the BDA to a North Korean account at a bank in Russia, via the US federal reserve.