North Korea sent a letter to the United Nations nuclear watchdog Saturday, inviting inspectors to the isolated country to discuss shutting down its main nuclear reactor, state media reported. The letter to the International Atomic Energy Agency said "a working-level delegation of the IAEA has been invited to visit (North Korea) as it is confirmed that the process of de-freezing the funds of (North Korea) at Banco Delta Asia in Macau has reached its final phase," the North's Korean Central News Agency reported. The inspectors were invited for "discussions of the procedures of the IAEA's verification and monitoring of" shutting down its Yongbyon reactor, KCNA said. North Korea has refused to act on its February pledge to begin disarming until it gets access to $25 million once frozen in a US-blacklisted Macau bank. The US accused Banco Delta Asia of helping North Korea's government pass fake US$100 bills and launder money from weapons sales. Signs of a breakthrough in the stalemate emerged this week as the North Korean funds were finally began to be transferred. The North has repeatedly said it will live up its promise to begin dismantling its nuclear program once the money is fully released.