The US has welcomed North Korea's decision to invite International Atomic Energy Agency monitors to discuss shutting down a key nuclear reactor.
North Korea says it will close its reactor once a funds row is resolved
White House spokesman Gordon Johndroe said the offer was a "good step". But the IAEA said it had not yet received the invitation from North Korea.
North Korean state media said the move was in response the release of funds frozen in a bank account in Macau.
A row over the funds stalled a February deal agreed on the reactor in Yongbyon.
Earlier, US Assistant Secretary of State Christopher Hill said the $24m (£12.1m) transfer of the funds had been delayed by technical problems in Russian banks.
The North Korean funds were frozen for nearly two years after the US said they were the proceeds of drug smuggling and counterfeiting, making other banks unwilling to touch them.
On Thursday, Macau government officials said the money had been transferred from Banco Delta Asia (BDA) to the US Federal Reserve.
It was then to be sent on to a North Korean account at a bank in Russia.
After Mr Hill's announcement, a statement on North Korean news agency, KCNA, said the country's atomic energy chief, Ri Je-son, had written a letter to the director general of the IAEA, Mohammed ElBaradei, inviting UN inspectors.
"He in the letter noted that a working-level delegation of the IAEA has been invited to visit the DPRK [North Korea] as it is confirmed that the process of de-freezing the funds of the DPRK at the Banco Delta Asia in Macau has reached its final phase," the agency said.
N KOREA NUCLEAR DEAL
N Korea to 'shut down and seal' Yongbyon reactor, then disable all nuclear facilities
In return, will be given 1m tonnes of heavy fuel oil
N Korea to invite IAEA back to monitor deal
Under earlier 2005 deal, N Korea agreed to end nuclear programme and return to non-proliferation treaty
N Korea's demand for light water reactor to be discussed at "appropriate time"
The UN inspectors were to visit for "discussions of the procedures of the IAEA's verification and monitoring of" shutting down the Yongbyon reactor, KCNA said.
Mr Hill told reporters in Mongolia that the funds had been transferred to Russia and he expected them to be paid into the North Korean account in the next few days.
"They're having some technical problems in getting it to the bank where the actual North Korean accounts are," he said.
Mr Hill did not provide details of the problems, however, but he said the US had first learned of them from the North Koreans.
The US envoy said he hoped the transfer would prompt Pyongyang to act on its pledge at the six-party talks to shut down and seal its Yongbyon nuclear reactor.
"We hope they will get on with what they need to do in terms of implementing the February agreement," he said.
North Korea has said in the past that it will begin the process of closing its reactor once it has received its funds.